You probably won't find any 3rd party software that is capable of directly converting Skillpipe digital publications (.bdb2) to any other format, including PDF, because BDB2 format seems to be proprietary and closed.
However, since Skillpipe reader supports printing, you may be able to print individual pages from your courses (.bdb2) as .pdf documents. The catch is that your .pdf document will contain a watermark including your name. But that shouldn't matter for personal use.
Be aware that copies are only authorized for personal use. Unauthorized copying and distribution of Courseware content is prohibited.