Common Problems
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Blank LDM screens
These usually mean that the system (LDM, vBulletin or php) is sending an unexpected error message. This may be caused by a code bug, or it may be caused by running out of resources.
By default, vBulletin compresses the data it sends to the user. This saves bandwidth but unfortunately, unexpected errors lead to a blank screen rather than producing the required error message.
Go to vBulletin->admincp->vBulletin options->Cookies and Header Options, disable GZIP HTML Output, go back to the page that was causing problems and try again.
Also, check whether your installation has disabled error reporting (i.e. if the php.ini file turns off display_errors). This is good practice (it improves security), but again means that you get a blank screen if something goes wrong. You can usually re-enable this on a temporary basis within a .htaccess file, using the line:
php_flag display_errors 1
or by creating a vBulletin plugin attached to the global_start hook, containing the line:
ini_set('display_errors', 1);
If these hints do not help you resolve the problem, take a look at the vBulletin troubleshooting guide.
Unable to create categories
Does your site use the Suhosin module? Its default settings do not allow LDM forms to submit all the required parameters. An early symptom is that, when you attempt to create a category, nothing happens. See Site Configuration.
Related to the vBulletin attachments table
- I'm setting bandwidth allowances/file download allowances but my users are still able to download as many files as they want
- Check that you've defined the filetypes in the VBulletin table. Otherwise LDM doesn't know that they are downloads.
- I want to upload filetype XXX but it doesn't appear on the list
- See previous question. Unless the filetype is in the VBulletin attachment table, then LDM doesn't know it can be uploaded either.
- My browser's showing an Internal Server Error message (error 500)
- This can happen when the VBulletin attachments table contains a mimetype record with no "Content-type:" string, e.g. you've set up the information for mp3's as "audio/mp3" instead of "Content-type: audio/mp3".
Related to system resources
- Fatal error - Allowed memory size of XXXX bytes exhausted
- Take a look at how much memory your web server is allowing you to use (php.ini setting memory_limit). The default setting of 8M is not enough to run patched vBulletin boards, e.g. LDM plus other hacks. Try giving yourself at least 12M. A much larger memory limit is needed if you want to create thumbnails of large image files using the GD library.
- I can't get file uploads and thumbnails to work
- Perhaps your web server places security restrictions on what can be done within your web site.
- Check directory permissions. On a Linux server, the directories in which the uploads and thumbnails are held should have chmod(777) permissions.
- Check the php.ini setting open_basedir, which restricts script access to certain directories. If open_basedir is blocking LDM, it is usually possible to get uploads to work correctly by turning on local_file_root and setting local_file_root_prefix appropriately. If open_basedir is set to block access to directory tree holding your web site, you will not be be able to cache thumbnails, but you will still be able to display thumbnails that are generated on-the-fly.
- Downloads of large files stop mid-way through with no error message
- This usually means that LDM has used its allowed CPU time/elapsed time before finishing the download. This is most likely to occur when downloading files that are held on a remote server or use full urls. Take a look at the php.ini settings max_execution_time and max_input_time and consider moving the files onto your own server/specifying them using local file names rather than full urls.
- My service provider is telling me I'm using far too much CPU time
- See the previous question - are you using full urls for your downloads?
- My database is growing huge and there are cpu spikes
- your download table has probably grown very large. Prune it by visiting LDM->Admin->Hits. Consider setting LDM->Admin->Settings prune_downloads.
Browser Problems
These typically involve the automatic launching of some utility program when the user requests a download, instead of allowing the user to choose what to do (e.g. save the file.) Adobe Acrobat, Windows Media Player are examples of such programs. The problem arises because the programs integrate themselves with the browser and override the default behaviour. Usually, it is possible for the user to disable or modify this behaviour, but the process can be complicated and is in any case out of your control.
For downloads (i.e. filetypes present in the vBulletin attachments table), you can overcome this problem using the LDM->Admin->Setting force_saveas setting to force the browser to offer a "save as" dialogue. However, this will not work for links. Instead, you must reconfigure your web server, see Configuring Filetypes in vBulletin.
Download Managers
LDM works correctly with download managers such as Flashget, Free Download Manager, etc, including responding correctly to requests for part of a file and establish multiple parallel connections to a file (so-called HTTP 206 Partial Content handling, based on requests for a *single* range - LDM does not handle multiple range requests).
If you make entries unavailable to unregistered users, and users report problems in using download managers, tell them to check the manager's cookie settings.
Other problems
- Link validation gets stuck with some sites
- Try using the cURL interface, which seems to work better than fopen() in this respect.
- Problems with Adobe Acrobat pdf files
- Adobe's plugins tend to take control of users' browsers. Advise users to disable Acrobat's integration within their browsers (change general preferences in Acrobat/Acrobat Reader or in Mozilla).
