I believe the problem is you don't have a Member in the system that has ADMIN code permission rights.

Could you confirm these things using phpMyAdmin:

* You have a member record containing ID = 1 in the Member table
* You have a Group_Members table with a record containing GroupID = 1, and MemberID = 1
* You have a Permission table with a record containing GroupID = 1 and Code = ADMIN

Am I right in assuming you dropped the database, and rebuilt from scratch to achieve the problem you're currently having? Or is it from a fresh 'untouched' database from the install?

Hope this helps,

Sean

I just thought I'd add that I encountered exactly the same issue upgrading from 2.0.1 to 2.0.2b which I just described (in less depth, but this jogged my memory), here:
http://www.silverstripe.com/general-discussion/flat/3143

I too, checked all of these things in phpMyAdmin and all are present.

I applied a patch to the GSoC branch that resolves this problem.. maybe you want to merge it into the trunk branch!? It's in r39559.

Maybe you need to merge also some of my changes to the Member class, namely Member::currentUser() and Member::isAdmin() respectively Member::_isAdmin().

Great. That means you should find it soon in the daily builds