Some problems with documents module

Hello,
Maybe somebody can explain to me whats wrong:

I created the document and attached the file, but when I tried to “download” the attached file I got the “HTTP ERROR 500”
I tried to work with Word documents, XML files but I get the same error.
when I tried to save the “link” (save link as), it’s try to save the “index.php” file, but also I get the error " Failed - Server problem"

If somebody have the solution, please send it to me

Thanks in advance,
Yvgeni

I have the same error… SuiteCRM 7.7.4

Any idea?

can you provide any more details, what environment are you running on, php version etc?