Great.....

I try to install the Webuilder on my website....
And now all created directories have a "test.txt" file on them, with 0 Byte.
Impossible to remove the script and the directory...

Not very cool...

test.txt is just we test if the folder is writeable. If the apache is the owner, then unfortunatelly you cannot delete with FTP user the file, cause is owned by apache :-(
The solution is to have Apache as CGI (mod_suphp), but for this you must ask your hosting company.