goto the control panel open the forum permission for that forum.
Double check
"Can post using Markup/UBBCode"
make sure there is a 1 not a 0 for the new group.
You will need to do it for every forum
so might as well goto Control Panel » Group Management
Select forum to the right of the new group.
open the Can post using Markup/UBBCode permission
and add a 1 to all the forums they have access to.
