What version of linux are you running?
Just on a side note, attached is a Linux cheat sheet I put together for the various Linux modules that can help you out as well in case you wind up doing stuff manually.
Hmm, VSEL 1.9 supports rhell 5+, so your good to go there.
I've had various UNIX mcafee modules not install through tasks, and have wound up doing a deployment task that runs on the hour for 8 hours straight, and usually after a couple days it will install. How do you have your deployment schedule set? Otherwise if its only 1 rhel box i would just manually install.