Mac crash upon completion of download

I installed the program, went through the learning process, and had no problems until I tried to download some files. Every time I tried to download a file, it seems to be working just fine until it completes the download. The statistics counter is incremented, but the file itself is lost and the computer crashes. Hard. A force quit application command fails to complete so a forced reboot is required.

I am not a regular here, but the documentation says this is the only place for non-pro users to get help if they wish to continue using the program. Thus, if you do have something useful to add towards the solution of this problem, please email me at <james13@mac.com>.