SL & Parallels 4: "don't have rights to use this virtual machine"

I upgraded to parallels 4 (latest build) and then installed SL. When logged in as administrator, Parallels boots XP fine (I installed XP in the "shared" user folder so that all users could use it. But when I log in as a non-admin user and try to open the "microsoft windows XP.pvm" to access windows, I get an error message that says "Access Denied - You do not have enough rights to use this virtual machine".
I'm assuming it has something to do with the mac os and privileges, but don't know how to address it.
The file path is HD>users>shared and all users have read/write permissions.

Any help would be appreciated!