port to 6.x well done.

I have tried it on Drupal 6.2 and it works, although I am getting errors from forum.module

warning: Missing argument 3 for forum_access() in /home/hutch/www/drupal-6.2/modules/forum/forum.module on line 313.

so I checked the new workspace.module and altered the lines 233 234
from

$can_edit = $function('update', $row) ? TRUE : FALSE;
$can_delete = $function('delete', $row) ? TRUE : FALSE;

to

$can_edit = $function('update', $row, $user) ? TRUE : FALSE;
$can_delete = $function('delete', $row, $user) ? TRUE : FALSE;

This is correct as hook_access requires 3 parameters, however it has not cured the problem although the forum topic is listed

I will continue debugging

Well it turns out that although hook_access does require 3 parameters the above fix is not required at all, but I have found the problem, it is in function workspace_form, line 329, added $user to the parameters there.
The attached patch is on workspace.module with rad1's workspace.diff already applied.

brilliant! We now have workspace in D6

To continue with the port to 6.x, here is a prospective workspace.module based on the above patches.
workspace.info should contain

name = Workspace
description = Allows users to list/manage their own content.
core = 6.x

I have it working on two sites.

6.x-1.0 is released.