I've seen a few of these problems lately where a user clicks on a link in PWA that should open a timesheet, a resource, etc., and instead, the user is rewarded with an "Error on page" in the lower left hand corner of IE.

In one case, we deleted temporary internet files using Tools > Internet options and that had no effect.  So we deleted the contents of this folder on the file system in C:\Users\<username>\AppData\Local\Microsoft\Windows\Temporary Internet Files and that prevented the problem.

In the other case, we ran a repair on Microsoft Office Professional 2010.  Below are my notes from the call:

On user's workstation, User accesses PWA > Server Settings > Manager Users.
He searches on a single user and attempts to click on the user's name to open the resource for editing.
Nothing happens except an Error on page in the lower lefthand corner.
'g_oFormPOst' is null or not an object
Logged into different workstation.
Signed into PWA, did same steps to repro and was unable to, so problem is on user's workstation.
Research indicates a repair of Microsoft Office will correct this issue; also clearing IE cache is an option.
Deleted IE cache via Tools > Internet Options.
Closed IE, reopened.  Repro is still possible.
Opened Control Panel > Programs and Features.
Right clicked Microsoft Office Professional 2010 > Change > Repair.
Allowed repair to complete.
User restarted workstation.
Repair fixed the issue; unable to repro the problem.

Microsoft Project Server 2007, 2010 and 2013 February 2013 CU Announcement here http://blogs.technet.com/b/projectsupport/archive/2013/02/14/microsoft-project-server-2007-2010-and-2013-february-2013-cu-announcement.aspx

You can also get the downloads from here: Update center for Office, Office servers, and related products http://technet.microsoft.com/en-us/office/ee748587.aspx

While I do receive a lot of requests for specific information and links from customers, I thought it worthwhile to point out some sites that are wonderful jumping off points to references online.  Enjoy!

Update center for Office, Office servers, and related products http://technet.microsoft.com/en-us/office/ee748587.aspx

This is the landing page for the latest CUs available.  From here, you can click the latest KB article link and pull the downloads.  The best part is, this site is updated so you can save this to your favorites and you can check it for the latest CU without having to go other places.

Project Server for IT pros (Home) http://technet.microsoft.com/en-us/projectserver/default.aspx

Project Server 2010 for IT pros http://technet.microsoft.com/en-us/projectserver/ee263909.aspx#tab=1

Project Server 2013 for IT pros http://technet.microsoft.com/en-us/projectserver/fp123546

Finding Project Server 2010 documentation http://blogs.msdn.com/b/project/archive/2010/09/15/finding-project-server-2010-documentation.aspx

Documentation for Project Server 2010 is spread across three websites: TechNet, Office.com, and MSDN. Each of these sites addresses a different audience. TechNet focuses on the IT Pro, Office.com focuses on the end user, and MSDN focuses on the developer audience. In addition to these three sites, blogs are also a great source of information.

Project Server 2010 IT-Professional TechNet Webcasts (On demand web casts) https://msevents.microsoft.com/cui/SearchDisplay.aspx?culture=en-us#culture=en-us;kwdAny=project%20server%202010;eventType=3;searchcontrol=yes;s=1

                This is canned URL for searching MS Events for online on-demand web casts.

Project Developer Center http://msdn.microsoft.com/project

Project Developer Center for Project Server 2010 http://msdn.microsoft.com/en-US/office/ee695847

Project 2013 for developers http://msdn.microsoft.com/en-US/office/fp161502

Project Blog for the Product Group http://blogs.office.com/b/project/

Microsoft Project Support Blog http://blogs.technet.com/b/projectsupport/

More blogs:

1.       Ben Howard (MVP)'s Blog Real life tales of Project Server

2.       Brian Kennemer (MVP)'s Blog brian kennemer endlessly obsessing about Project Server so that you don't have to

3.       Project Programmability blog This blog focuses on customizations and programming for Project Web App, Project Server, Project Professional and Project Standard

4.       Christophe Fiessinger's Blog  No longer Project, but still very useful

5.       Advisicon Blog Microsoft Project and Project Server

6.       Jan Kalis's blog - dedicated to Microsoft Project Partners and Microsoft Project News, updates and top-of-mind for Microsoft Project Partners and Microsoft Project.

7.       All about Enterprise Project Management (EPM)  Khurram Jamshed's blog

8.       MSProjectExperts (MVPs) blog Project Server Help Blog

9.       Office Sustained Engineering Blog Microsoft Office Updates - The official blog of the Office Sustained Engineering and Release team.

10.    PJ Mistry's Blog Microsoft Enterprise Project Management (EPM) and SharePoint - Blog by PJ Mistry (EPMGuy.com)

11.    Rolly Perreaux (MVP)'s Blog Microroft Project Server, SharePoint, Security and other cool things...

12.    Treb Gatte's Blog About MS Project - Life after the Installation

13.    Sam Huffman (MVP)'s Project Blog MS Project and Project Server Blogspot - the WinProj Blog!

14.    Andrew Lavinsky (MVP)'s Blog Project Epistemology - Enterprise Project Management with a Microsoft Focus

15.    Alex Burton (MVP)'s Blog A site covering all things Microsoft Enterprise Project Management.

16.    Jim Aksel (MVP)'s Blog Jim Aksel (MVP)'s Blog

17.    Jack Dahlgren (MVP)'s Blog Project Management, Software, Training...

18.    Nenad Trajkovski (MVP)'s Blog