Should have read their site before buying.
"The following products are NOT supported under Mac OS X 10.6:
Iomega REV drives:
Iomega REV drives are compatible with Mac OS X versions 10.4 and 10.5, but are not compatible with Mac OS X 10.6 due to a UDF driver conflict that will not be fixed. Iomega will continue to provide technical support and warranty services for the supported operating systems."
http://tinyurl.com/yk44dll