Here's ONE Work-Around ... (It WORK'd! for ME!):
After the GeekLog 2.0.0-(rc3) INSTALL ... (and before you login with your 'Admin' and 'password'

.
1. Run the following UPDATE-QUERY on your GeekLog-DATABASE:
<<<
update plugins set pi_enabled=0;
>>>
2. Login to your GeekLog 2.0.0-(rc3) with your default 'Admin' and 'password'.
3. Click the link "Plugins(6)" and MANUALLY Re-Enable ALL of your Plug-Ins.
-
The Extra-Performance was Immediately-Obvious AND I LUV the LOOKs!

of the ... 'Denim' Theme
AND
I was able to figure out how to get my Big-Grubby-Hands on the Forum-2.9.0 Code-Files !!!
You Geek-Guys need to maintain a Updated-(easily-found)-Download for the New-Forum-2.9.0 !!!
I'm beginning an install of Forum 2.9.0 as soon after I get this ... POST'd
We should make a better list of which plugins are not compatible so the users can disable them before hand.
The 2.9.0 forum code hasn't been officially released yet but is usuable (this is what Geeklog.net is currently using). There will be a few more bug fixes done before an official release hopefully in May sometime.
Tom