[Andreas]

Theoretically, this is the correct code, but as you need a variable as part of the key for $vbcollapse parsing fails.
(To see what I mean just put $foo[foo_$bar] in an empty template and try to save it)

Therefore you must construct variables in PHP that hold
$vbcollapse["collapseobj_forumbit_$jbgenre"]
$vbcollapse["collapseimg_forumbit_$jbgenre"]

I forgot about this problem when posting the code as I did not try to compile it