Lionel, within the forum itself does it switch proper?
Secondly: do you have the forum in /forum, and the site in /, or something similar? or are the forum and portal both in the same directory?
Thirdly (and lastly): vbadvanced or vbadvanced CPMS, and which version?
My beta tester, AzhriaLilu, ran this hack succesfully on a modded 3.0.3. with vbadvanced CPMS, perhaps it's a 3.0.1. specific issue, or doesn't work with the standard portal out of the box. I'll have a look either way.
It's been tested solely on 3.0.3. (with various previous modifications on 3 of the boards), which is why I listed it as a requirement in the instructions.
I'll get back to you on this, with some changes perhaps it can be made tick for 3.0.1. and vbA as well. *goes and finds the 3.01 installer*