When I try to assign categories and rebuild my site, rebuild errors out with the following.

Reading from filehandle failed at lib/MT/FileMgr/Local.pm line 128

MT::App::CMS=HASH(0x8360b24) Use of uninitialized value in concatenation (.) or string at lib/MT/Entry.pm line 234.
MT::App::CMS=HASH(0x8360b24) Use of uninitialized value in concatenation (.) or string at extlib/File/Spec/Unix.pm line 78.
MT::App::CMS=HASH(0x8360b24) Use of uninitialized value in concatenation (.) or string at lib/MT/Template/Context.pm line 1690.

I have looked in the database and the categories for all my entries are being set to 'null' although the category table is populated. Everything else seems to be getting populated correctly.

I am using Mysql.

Does anyone have any ideas? Thanks.

Are you using any Archive File Templates to control the location/naming of your archive files?

That was one of my problems. It fixed the rebuild errors but there are still no categories attached to my entry in the database (looking at the "mt_entry" table). My category archive mixes all entries together. When I manually edit the database to add the category designation, my category archives build correctly.