During the past couple of days I'm unable to access APEX workspace, I had no issues in the past. My environment is APEX 4.1, EPG & APACHE server, windows server 2008 64 bit. I'm able to access the APEX applications and the Internal Admin without any issues, it's only when I try to access the workspaces I get the page cannot display error 404. The database alert log shows the following error after a complete shutdown and as soon as we access the workspace (only when we try to access the workspace) no error when we access the applications or the admin space*:
Completed: ALTER DATABASE OPEN
Wed Sep 08 14:01:24 2010
QKSRC: ViewText[ecode=942] = SELECT /*+ result_cache */ CASE WHEN FLOW_ID = 4411 THEN 'NATIVE_' ELSE 'PLUGIN_' END||NAME AS NAME, ':'||STANDARD_ATTRIBUTES||':' AS STANDARD_ATTRIBUTES FROM WWV_FLOW_PLUGINS WHERE FLOW_ID IN (4411, :B1 ) AND PLUGIN_TYPE = 'ITEM TYPE'
Wed Sep 08 14:04:05 2010
Exception [type: ACCESS_VIOLATION, UNABLE_TO_READ] [ADDR:0x0] [PC:0x97C5123, pfrinstr_BRNCNULL()+55]
Errors in file d:\app\ag-admin\diag\rdbms\agdev\agdev\trace\agdev_ora_14324.trc (incident=30478):
ORA-07445: exception encountered: core dump [pfrinstr_BRNCNULL()+55] [ACCESS_VIOLATION] [ADDR:0x0] [PC:0x97C5123] [UNABLE_TO_READ] 
Incident details in: d:\app\ag-admin\diag\rdbms\agdev\agdev\incident\incdir_30478\agdev_ora_14324_i30478.trc
May be for some reason your Admin and Developer users appear to have got locked. End users have no lock checking and hence not affected.
1. Login as Internal / Admin
2. Go to Home- Manage Workspaces- Manage Developers and Users
3. Edit the Admin and Developer users one by one
4. Check Account Availability. If its Locked then you have found your problem. Make it Unlocked and Apply Changes
By the way all the objects int the database are valid. I started the APEX 4.1 with the EPG at the begining then I installed the APACHE from the webtier tools. Before I installed the APACHE i was able to login to the workspaces no problem. I can access the application using the EPG and the APACHE without having any issues. Now, no matter which method I use to access the workspaces, it always throw the error page cannot display 404 .... etc. Every time I try to access any workspace I get the same error reported above in the first post.
we had a Virtual Circuit wait is running high error (some performanace issues when we used the EPG), our old environment was always APACHE, we never had any problems with the APACHE. Now the new environment is windows server 2008, 64 bit. Oracle APEX support suggested we install the APACHE while the number of users exceeds 100. we noticed a great differece in page load time when we installed the APACHE (much faster), but we can't access the workspace now!!?? APACHE is much faster than the EPG in our environment. We are able to access all the applications and the Internal Admin space using both methods (no problem at all).
APEX_PUBLIC_USER and the password is setup correctly, remember now that I can access all my applications, the issue is accessing the workspace. All post installation requirements are also setup correctly.
1. Login as Internal Admin
2. Go to HomeManage ->Workspaces->Workspace Details
3. Click the Edit icon on one of the workspaces to which you do not have acess currently.
4. Scroll down to Component Availability
5. All the 4 select list items must be Yes.
If all the 4 are already Yes then try this.
1. As Internal/Admin go to HomeManage InstanceSecurity
2. Verify the the 4 select lists in the Security section are Yes,No,No,No.