phpBB 2 import errors: private messages, files

Hello,

I was having problems importing my phpBB 2 forum into Drupal - the module was issuing incorrect SQL statements:
* the query checking private message duplication was lacking aliases and generated errors,
* the statement to insert files into the {files} table was referencing incorrect columns and the necessary {upload} table modifications were not made (D5 heritage?),
* the statement to attach files to comments using the comment_upload module was referencing incorrect columns and the table name was also incorrect.

This patch solves these problems and sets the input format also for comments, not only the topic node. It uses the same setting as for nodes. The patch is against 6.x-1.4.

The relevant module versions in my installation are:
* Drupal 6.8
* phpBB2Drupal 6.x-1.4
* Comment Upload 6.x-1.x-dev (2008-Dec-11)
* Privatemsg 6.x-1.0-rc2

Please check it out. Hopefully we could include the patch in a future 6.x-1.5 release.

Marcin