Is there are support for formats besides the ones already set by default when searching for video files? Also is there are way to delete an account with these forums?

I'm not exactly sure what you mean. Normally xvid & divx files are saved using an extension like avi or mov, etc. depending upon platform & application. On Mac OSX Divx files are saved with an extension of .divx This is not one of the default shared extensions in LW. So it would need to be added under LW's preferences, Sharing, shared extensions.

If you're searching for videos that may have been encoded with those codecs, you could try including it in the search.
eg: video title - divx

Only a forum administrator like myself can delete a member account. If it is desired then send me a personal message explaining reason & account name; eg: more than one user account. If you want to change email address or user-name that can be done also.