Make sure that there are no special characters in the document  name
or folder name that you are trying to create.

I get this error  when i click on the link to "Add document"

it doesnt even ask me for name of the folder or document

Have you tried rebooting your server? I do not have a specific answer to your
problem, but I would suspect some service failure, and rebooting will cause all
services to restart.

I did that, it does work fine after a restart . But after some time
the error  pop[s up again.

also I can see following error  message in the source of the same page

<DIV name="ErrorContext" style="display: none;">
Error Number: 3706 (0xE7A)
Error Description : Provider cannot be found. It may not be properly
installed.
Error Source: ADODB.Properties
Error Context/Call Stack:

GetUncachedConnectionObject() - Error enabling Wininet Password Cache
flushing on ADO Connection object.
BindKnowledgeObjectToRow() - Error getting uncached connection object.
DisplayErrorSummaryAndExit() - strEndUserContextMessage =
</DIV>