when users register as a students in a lan network, some user can't play scorm course!

An alert appears: "object error",

click OK and then click at javascript error symbol i see: 'undefined' is null or not an object

 'undefined' is in unpackaged scorm course folder.

 I don't know why! because i use internet explorer 6 SP1 for win2k server and i think 'undefined' is a constant of javascript!

Please help me!