access denied on all nodes

I just installed spaces, but enabling it causes these sql errors on every node, with an access denied message:

warning: array_fill() [function.array-fill]: Number of elements must be positive in /home/yeaadmin/public_html/2010/includes/database.inc on line 253.
warning: implode() [function.implode]: Invalid arguments passed in /home/yeaadmin/public_html/2010/includes/database.inc on line 253.
warning: array_keys() [function.array-keys]: The first argument should be an array in /home/yeaadmin/public_html/2010/modules/user/user.module on line 502.
user warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')' at line 1 query: SELECT p.perm FROM role r INNER JOIN permission p ON p.rid = r.rid WHERE r.rid IN () in /home/yeaadmin/public_html/2010/modules/user/user.module on line 502.

My modules are:

Module Grants 6.x-3.4
CTM 6x-1.0
CCK 6.x-2.6
Chaos Tools 6.x-1.7
Context 6.x-3.0
Drupal core 6.15
Features 6.x-1.0
Nodewords 6.x-1.11
Boxes 6.x-1.0
FCKeditor 6.x-2.0
Global Redirect 6.x-1.2
Menu Block 6.x-2.2
Path redirect 6.x-1.0-beta4
Pathauto 6.x-1.2
Token 6.x-1.12
Spaces 6.x-3.0
JQuery UI 6.x-1.3
Insert view 6.x-1.0
Views 6.x-2.8
WebFM 6.x-2.11
XML sitemap 6.x-1.2

The error occurs for user 1, all other users and anonymous. I didn't install OG, Purl or Strongarm - maybe there's a dependency on one of these?