Informed Webmaster

Since this issue is only with the main theme of your website, i would take a close look at that theme.
Here is something you may want to check:
- All files and folders are there, including the lang_iso folders
- Make sure the forum has read permission to the files and folders
- Files have the right file-extension(maybe try to disable the extension that changed the logo file extension)
- Remember to purge the cache after you have made any changes, to see if the changes work

As a last resort, you could send me the theme files, so i could check them out(if you don't have a problem with that).

Not many files and folders, but i can see it uses prosilver as its parent, so that should make up for it. I will test it out on my test forum setup and see what i find.

Adding a gif image "site_logo.gif" to the folder "ilDraGoNeRo_Styles_Dark_Red/theme/images/" seem to fix the issue.

But there isn't, so what should be there is not there. Well, it least not in the compressed file you uploaded. So "site_logo.gif" it's not there, and without it all user location was set to the index page on the test forum i setup, however when i added the file "site_logo.gif" (i just created a transparent gif image to test with) and placed it in the folder "ilDraGoNeRo_Styles_Dark_Red/theme/images/" everything seem to work like it should.