Which one of the user-contrib programs is it? If it is an ENVI program, or if it uses any of ENVI's functionality, you will need and ENVI license to run it. You are most likely getting an "Undefined procedure/function" error, correct? That is because ENVI is not installed with the normal IDL installer (though the ENVI installer includes IDL). So you would need two things, to install ENVI, and an ENVI license. -Josh ITTVIS