C:\QuikZip.exe C:\file.txt Compress
When entering arguments - be sure to separate each with a space.
And also there should be no spaces in the arguments themselves.
*You can also just drag 'n' drop a file onto the application's icon and it will compress/decompress it automatically. The <MODE> will be determined by the extension of the <INPUTFILE>; if it's extension is ".gz" then it gets decompressed, or else it gets compressed.