Make sure the initiators are using the Virtual IP to make the iSCSI connections.
If there are any allow/deny rules or CHAP authentication being used, this needs to be the same on each node to allow proper connectivity.
This may help in the setup :
http://www.open-e.com/library/webcasts-and-videos/
Open-E DSS V6 AutoFailover with VMware 4.0 - Webcast