ntdll.dll problem when accessing a website

Hi hope you can help. I have a Dell 1525 windows vista and the following problem has started to occur when I try to access my work website, which is a https site. This has always worked fine before and I don't know this is occuring.
Thank you

Product
Internet Explorer

Problem
Stopped working

Date
15/04/2009 13:56

Status
Report Sent

Problem signature
Problem Event Name: APPCRASH
Application Name: iexplore.exe
Application Version: 7.0.6001.18226
Application Timestamp: 49ac95d6
Fault Module Name: ntdll.dll
Fault Module Version: 6.0.6001.18000
Fault Module Timestamp: 4791a7a6
Exception Code: c0000028
Exception Offset: 00080ea0
OS Version: 6.0.6001.2.1.0.768.3
Locale ID: 2057
Additional Information 1: bfef
Additional Information 2: e8adce1c2b9e7be834b4063ac3c53863
Additional Information 3: bfef
Additional Information 4: e8adce1c2b9e7be834b4063ac3c53863

Extra information about the problem
Bucket ID: 1228214496

If Windows is unable to run applications due to a .dll error, this .dll may be missing or you may have registry error. Such errors can heavily influence the performance of your PC. We strongly recommend that you run any free registry scan on your pc.

Have you noticed that your computer, runs slower and it crashes more often? Installing and uninstalling programs leaves behind fragmented entries such as orphaned tasks, corrupted drivers (which most of them are DLL files) and other erroneous forms of registry keys.

Over time the registry gets cluttered and conflicts start to emerge. If left unchecked, your system will become increasingly unstable, performance will whine down and your system starts to crash more frequently.

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Cause of ntdll.dll error occurrence -
The causes of ntdll.dll error messages can vary greatly. However, most ntdll.dll errors result from a corrupt or damaged version of the ntdll.dll file itself, corrupt hardware drivers, or issues between Windows and other programs.

Solution -

• Selectively disable Internet Explorer add-ons.
• If your ntdll.dll error is displaying when you start, run, or close Internet Explorer, an add-on may be causing the problem.
• Disabling each add-on, one by one, will determine which add-on is the culprit (if any).

Thank you, problem solved.