Hello;
try to check what is displayed if you upload a file "index.htm" in your gallery root. Maybe the server tries to serve html pages prior to php pages, but I doubt.
Try also to get errors displayed by changing this line in "global.php":
error_reporting(E_ERROR | E_WARNING | E_PARSE);
by:
error_reporting(E_ALL);
Fantastico requires certain files and directories to have the following permissions:
NOTE: Depending on your server setup, the files may be in slightly different locations.
Files:
/bin/tar 0755
/bin/gzip 0755
/usr/bin/wget 0700
Directories (create if they do not exist):
/tmp 1777
/usr/local/cpanel/base/tmp 1777
/usr/local/cpanel/3rdparty/tmp 1777
(try to empty all tmp directories)
If nothing works, you may log into the Fantastico Admin area and go to Get/Update Files and upgrade Fantastico (the core files) and the master files (scripts). Then run the Detect/Fix Common Problems item.
I'm not a Fantastico user, but some friends are and faced some light problems with cpanel, but none like yours.
BTW, hope it could help a little and you could succeed.