If it worked for you from the CMD prompt but it does work from SSIS, I have to ask... is SSIS on the same machine that you had the successful CMD prompt run on? SSIS won't be able to see you local C: drive if it's on a different machine unless you use a UNC instead of a file path AND you have to give SSIS privs to see your machine.

A better way would be to copy the file to the SSIS machine and try again. 7-ZIP must also be installed on the SSIS box.