error 500 on file manager

[kroom]

Hi all,
I used to post on the old forum, so is likely we have met before.
My TL was set up a year ago (v. 2.6.3), it was heavily used, and never had problems; now something has happened. I'd like to try to fix it, rather than update/reinstall, because it' s a quite complex install with several extensions.

I've two issues, involving file manager (but only logged as a particular user) and system log (when logged as admin); don't know if these are related.

1) One of my users (not admin) when clicking on "file manager" in backend, after a suspicious delay gets an error 500 (on IE, Firefox shows a completely blank page); for the other user, belonging to the same group without overrides on permissions ("use group settings only" for both users), no problems. It was reported to me that the first time this error showed up was after an image load. For this particular user, file manager is "dead".
Since this first happened -as reported- loading an image, I tried to disable thumbnails for that user (unchecking "Show thumbnail images" in user's settings): file manager was back!
Disabling thumbnails works, but it's only a temporary workaround!
System/html folder is chmod 777, with about 300 files.
Is there something I can do? maybe manually removing thumbs using FTP, or checking chmod on folders? if needed, I can give system/logs/error.log.

2) When I log as admin, clicking on "system log" in backend gives me an error 500 (blank page on Firefox); file manager is OK.

Any help would be greatly appreciated.
Thanks in advance,
Cristiano.

[qrczak]

Some time ago I had something similar. Probably you have to assign more memory in php.ini.

[kroom]

Thanks for your advice, but I don't understand why my file manager issue involves only one of my users and not the other, or me as an admin.
The website is hosted by a third party, so I'd wait until completely sure about the memory issue. :roll:

[kroom]

These are the settings on the server (caught with TL check tool):

Safe mode Off. Recommended setting is Off.
Maximum execution time 150. Recommended setting is 30 or greater.
Memory limit 24M. Recommended setting is 16M or greater.
Register globals Off. Recommended setting is Off.
File uploads On. Recommended setting is On.
Upload maximum filesize 8M. Recommended setting is 8M or greater.
SOAP extension On. Recommended setting is On.

Memory limit is 24M. It's of some relevance to better understand the problem?

Thanks,

Cristiano