Try stopping, and then restarting the Windows SharePoint Services Web
Application Service in Central Admin, Services on Server.

We had this same issue on a production machine last week.

A SharePoint process had failed leaving the IISMETABASE locked.

An IISRESET solved the problem.

I ran into the same problem and was just now opening up my email to
compose a new message to this list regarding the solution.

Just my guess to the problem:

It correlates that Event Viewer gives me an XML Exception error access
denied when this happens. It is like it isn't letting me open the
web.config for some application.

Perhaps one of the services on the server has a file in IIS locked.

In any event, when I restart the timer service IIS Manager works again.

We now have an stsadm.exe extension that resets owstimer.exe and/or
child processes. You can download it for free at our premium content
area at www.mindsharp.com. Kudos to Paul Schaflein for this brilliant
piece of custom code (he is one of the Barracuda Tools Developers)

Here's a quick overview:

Restart Timer

stsadm -o restarttimer

{ -farm | -server <server name>;<server name> }

[-exclude <server name>;<server name>]

Restarts the Windows SharePoint Services Timer service

on servers in the farm.

Use the -farm parameter to restart the service on all servers

in the farm that have the service installed.

Use the -server parameter to specify the servers on which to

restart the service.

Use the -exclude parameter in conjuction with -farm to restart

the service on all servers except those listed.


Enumerate Timer Jobs

stsadm -o enumtimerjobs

[-view {service | webapp}]

[-service <service name>]

[-webapp <web application url>]

[-schedule]

Displays the Timer Job Definition information.

Start Timer Job

stsadm -o starttimerjob

{ -service <service name> | -webapp <web application url> }

-job <job name>

[-schedule]

Displays the Timer Job Definition information.