Switched On Tech Design

Category: Troubleshooting

  • New CentOS WordPress install: Error 500

     

    Was asked to troubleshoot a client’s installation technique for WordPress on CentOS 6.x yesterday; they were receiving an Error 500 when they tried to access index.php for the first time. Checking the Apache logs showed:

     

    SoftException in Application.cpp:431: Mismatch between target GID (522) and GID (65531) of file “/home/andrea/public_html/index.php”

    Premature end of script headers: index.php

     

    What was happening was that the client was un-tarballing the latest.tar.gz file as root and then changing the ownership of the file with the following:

     

    chown -R [user] *

     

    Changing that command to:

     

    chown -R [user]:[usergroup] *

     

    e.g. here:

     

    chown -R andrea:andrea *

     

    fixed that error. By not specifying the new group there was an ownership mismatch where the system expected one group but got another. There are many  causes for an Error 500 – it’s a good habit to check the Apache logs first for pointers as to where to start troubleshooting.

  • New Mediawiki install produces error “Fatal exception of type MWException”

     

    Saw this on a new Mediawiki install where all of the optional extensions were selected, LocalSettings.php had been uploaded to the server and that’s as far as it would go.

     

    To fix, open up LocalSettings.php and comment out the line:

     

    require_once( “$IP/extensions/LocalisationUpdate/LocalisationUpdate.php” );

     

    You should now be able to refresh the main page and start using your wiki.

  • MythTV backend DVB adapter error: ERROR_OPEN

     

    If you see the above error when you’re trying to set up your DVB tuner card one cause is that MythTV can’t get access to the tuner card. This can be because there’s another application installed which has access to it, e.g. something like TVHeadend. On XBMCBuntu you can uninstall TVHeadend by running the following:

     

    apt-get remove tvheadend

    apt-get purge tvheadend

     

    …then retry the setup. If that was the problem it should pick the tuner up now without issue, showing the tuner name in place of ERROR_OPEN.

  • Windows 7 – Stopping a Wacom pen from right-clicking on a long press (aka press and hold)

     

    This is a personal bugbear which I encounter every time I reinstall a W7 OS. The problem is that when you hold the pen down – like you might when you’re trying to highlight text – Windows has a default setting of assuming that you wish to right click, which interrupts the selection you were making in an extremely irritating fashion. This isn’t a setting in the Wacom tablet settings, either, so it can be a little hard to find. The solution is in the Windows “Pen and Touch” settings (hit the Start button and then type “Pen” and you should see it as one of the options).

     

    Pen Options -> Press and hold -> Settings -> untick “Enable press and hold for right-clicking” -> Click OK -> Click Apply.

     

    While this may be a handy option for pens which don’t have a right-click button it really only serves to be a hindrance for a lot of Wacom users, it seems.

  • Lightroom 4: “Sort” option/dropdown box missing from Library view

     

    This one isn’t related to computer parts for a change but is something that happens to me regularly – I’ll import a handful of photos and want to sort them by capture time, but the “sort” box is missing from the Library view in Lightroom 4.0. You can bring it back by pressing T.

     

    I don’t know how it is I keep on accidentally hitting T but it seems I must do so regularly judging by how often this happens…

  • ZFS on Ubuntu error: Failed to load ZFS module stack

     

    If you see the above error in a fresh installation of ZFS on Ubuntu one cause may be that the package build-essentials wasn’t installed prior to installing the ubuntu-zfs package; run:

     

    sudo apt-get purge ubuntu-zfs

     

    then check for the remaining packages with the following:

     

    dpkg –list | grep zfs

     

    …and apt-get purge any remaining relevant ZFS packages.

     

    Then:

     

    sudo apt-get install build-essential

     

    …then install ubuntu-zfs as you did originally:

     

    sudo apt-get install ubuntu-zfs

     

    This time it should take properly. This isn’t the only cause of that error but on a fresh install with a new OS it’s one possibility.

  • Network Troubleshooting: Wireless N connecting at 54Mb/s

     

    This one came up today with a customer who was extending her Wireless N home wifi network with a wireless access point. The access point was reporting a Wireless N connection at a speed of 54Mb/s rather than 150 or 300Mb/s, and transfer speeds for anything connected to the access point were only 2-3MB/s (not unusual for 54Mb/s). The problem in this case ended up being that the access point was set to TKIP encryption rather than AES – using either WEP or WPA-TKIP may drop speeds back to Wireless G speed, which is 54Mb/s max.

     

    Switching the encryption to AES put speeds back to what they should be. This won’t always be the solution but it’s worth checking if you’re seeing that issue.

  • Asus motherboard BIOS update error: CAP file not recognised EFI bios!

     

    If you see the above error – and you’re selecting what you’re sure is the proper CAP file – chances are you’re trying to use a USB disk formatted to NTFS rather than FAT32. Frustratingly, the error message for a corrupt/non-CAP file is the same as the error message you get when you’re trying to use an NTFS-formatted drive, which Asus Ez Flash 2 is not compatible with.

     

    The solution is simply to use a FAT32-formatted drive. If that doesn’t work double check that your file hasn’t corrupted during the download and is complete, and the right BIOS for the board.

  • esxcli: Update/patch produces “Could not download from depot” error

    In ESXi 5.1 you can patch using the following command:

     

    esxcli software vib install -d /path/to/patch.zip

     

    If you’re getting the following result (using ESXi510-20121001.zip as an example):

     

     [MetadataDownloadError]
    Could not download from depot at zip:/var/log/vmware/ESXi510-201210001.zip?index.xml, skipping ((‘zip:/var/log/vmware/ESXi510-201210001.zip?index.xml’, ”, “Error extracting index.xml from /var/log/vmware/ESXi510-201210001.zip: [Errno 2] No such file or directory: ‘/var/log/vmware/ESXi510-201210001.zip’”))
    url = zip:/var/log/vmware/ESXi510-201210001.zip?index.xml
    Please refer to the log file for more details.

     

    This results from not putting in the absolute path to the .zip – e.g. using:

     

    esxcli software vib install -d ESXi510-20121001.zip

     

    rather than:

     

    esxcli software vib install -d /vmfs/volumes/datastore/ESXi510-20121001.zip

     

    Putting in the full path to the .zip file should resolve that error.

  • Error Code 60 on an Asus Z9PE-D16

     

    Today a customer’s Asus Z9PE-D16 wouldn’t boot and displayed the debug code 60 – in this case the problem was that the RAM sticks (8 total, 4 for each CPU) were in the black slots rather than the blue slots. Swapping them across resulted in a boot straight away.

     

    Hope that helps someone!