Does not compress most files that I try

I have had this program for about 12 months, and has not met my needs 90% of the times that I have tried it. I am a faculty member and commonly create very large PowerPoint presentations. Most of the presentations are 4-5mb in PowerPoint and become 5-8mb once they are saved as a PDF. I bought this program hoping to compress those PDF files to 2-3mb prior to distributing the files to students. However, about 90% of the time, I get an error, that even if I compress to 72 DPI with low resolution, the file size “cannot be reduced” with PDF squeezer. I am now looking for another similiar application to fulfill this need that is unmet by PDF Squeezer.

Dr Swan about PDF Squeezer 3