In case anyone is having problems with attachments, this might help.
WebIssues comes pre-configured with quite a low attachment limit - above that limit all attachments are put in a folder as files. However you may not want this behaviour, for all sorts of reasons (security being just one of them).
If you raise the pre-configured limit, you'll start getting errors when uploading attachments with a MySQL back-end. This is because MySQL comes pre-configured with a 1M size limit.
To change this you'll need access to your server's my.cnf or my.ini files. In my case, /etc/my.cnf needed the following added to it:
followed by a mysqld restart. That gets me to 16M which is all I'm prepared to accept on the basis of inconveniencing other users during the upload process! Something I'm looking at is whether WebIssues could automatically zip and split (into multiple archives) attachments :-)