0.6 Will soon be released, fixing many issues with the "undefined variable" problem, the report permissions bug, and the line item entry problem on invoices. I have implemented a Subversion server to track all the changes and hopefully allow people to contribute. You can reach the up to the minute source code for phpBMS through the following server:
svn://204.249.249.136/phpbms
For more information on subversion, including client software (I use TortoiseSVN for my client) visit http://subversion.tigris.org/
We will also be releasing a simple tutorial on using phpBMS in the following weeks.