Something similar has been reported before. .icl files are basically PE files (exe files) with resources in them, meaning they can be 16bit or 32bit files. Windows7 no longer supports 16bit .icl files.
Check if the .icl is 16bit, and if it is you'll need to convert it. The easy way to do this is to get an icon editor that supports .icl and just re-save it. The newly saved .icl package should work.
