If you have a tape stuck in a drive and it won't eject here's a quick fix that will work with most drives.  First, power down the drive.  Now press and hold the eject button and power up the drive, continuing to hold the eject button in until the tape ejects.  Obviously if your drive is an internal one you will have to power down the system it's connected to.  In most cases, if this works you'll be able to use the drive again without issue.  I don't have a technical explanation for what happens so I'll just say that the drive apparently got its "eyeballs crossed" and needed to be reset to release the tape.