A few suggestions to get you started....
1. If you myust use a more descriptive title...."help me" does not let us know the question, if you posted the question as "Need help mounting media in RHEL5" then more people might pick up the thread.
2. More specifics are needed. You said the media was working under Windows, but not mounting under Linux. Is this media CDROM, Floppy, Thumb Drive, PATA hard drive, SATA hard drive, SCSI drive DVD Drive....
There are a lot of different media.
Tell us more about your computer setup and type of media you are installing etc. More people can offer help after we know more.