Well I can't seem to find the post currently.
First item to check is:
Control Panel » Permission Checks
You should have a OK on all folders.
If not then you need to follow the install docs and correct the file folder permissions via say FTP.
For your issue look for anything that starts with Gallery.
Second item would be what graphics library you are using.
GD2 is usually safe because it is preinstalled with PHP. If you are using ImageMagick then maybe the host changed the location.
So I would change to GD2 to test.
Control Panel » Gallery Settings
What Graphics Library do you want to use?
Elect GD2 and save
That would be a start.
It would be nice to have a URL to the forum in question.
Blue Man Group
There is no such thing as stupid questions. Just stupid answers