It is possible to export .pjr projects to AVI videos using DVDx software. However, there is really no way how to convert .pjr file to .avi without DVDx and other no other program can help you here.
Convert DVDx project file to Audio Video Interleave movie.
We found one software available in the database for this conversion.
Microsoft Windows software - convert pjr to avi on Windows
A dVD backup software
Convert from pjr file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.