Problem with File Associations

I've created a program similar to Winzip. It takes command line arguments
like this:

zip file1 file2 ... fileN

I've added this Keys to Registry:

HKEY_CLASSES_ROOT\*\Shell\MYZIP
HKEY_CLASSES_ROOT\*\Shell\MYZIP\Command = "[PROGRAM_PATH]\Myzip.exe" %1


Here is my problem: when I select (for example) three files and try to
"MyZip" them, Three Myzips.exe is executed instead of one with three
arguments.


Thanks for your help