Attaching files to forum posts is restricted to the following types: gif - jpg - png - zip - rar - tar.
Please make sure that you use lower case, because attachments with extensions in upper case (capitals) are rejected. The maximum size is 200000 bytes. Other requirements are: no spaces in the file name, not dots in the file name other than the one in front of the file extension and only alphanumerical characters and '-' and '_' are allowed.