To be honest, I don't know that answer -
BUT I suspect its the problem -
Google 'GD temp files'
here's an unanswered post - sound familiar??
http://www.webhostingtalk.com/showthread.php?t=356468You might look in the root of your C:\ drive.
I have had the same problem with similar tools, particularly on Windows Server (I have 2 W2k3 servers used to host many sites and forums).
You could use Java DiskReport (or another disk usage tool) to see if you have a folder that should not be jam full of stuff.
Here's another question/thought or two ->
Did this start when you updated something apparently unrelated?
Another possibility - the functions are timing out - you probably couldn't tell from INSIDE you network.
I think Coppermine uses GD, I'll have a look on one of my servers that runs it and see if I can tell where its doing things... The difference is - I am running IIS on that server, not Apache.
Oooo (last thought for now)- Did you recently switch from ISO encoding to UTF8 by any chance???
Good Luck