how do i configure cpg to upload .doc or other files?
by default, the current stable release (cpg1.3.2) let's you upload docs, so I don't understand your question in the first place. For details, check the documentation (http://coppermine.sourceforge.net/manual.php#config_picture_thumb_advanced) that comes with coppermine.
Posting a link and test user account (non-admin) with upload privileges might help as well.
Joachim
may i know which types of files can be uploaded?
Have you read the documentation yet?