You will need to replace the drive wheel. If your system is less than 1yr old, you should contact your dealer for a replacement. If your system is over 1yr old, you can order replacement drive wheels from www.quilttech.com. Replacement drive wheels come in a set of 2, so even if you need to replace both, you only need to order one set. Other IQ parts that can be ordered from www.quilttech.com include the sensor wheel and o-rings.
Instructions for replacement can be found in the attached file.