Microsoft has a "supposed" explanation but is mostly technical talk with
little help.
( See:  http://support.microsoft.com/?kbid=141117  )

My first suggestion would be to re-install Windows Media Player to see if
you can replace (fix) the "bad" file.

Are these AVI, MPEG movie files coming from the web or are they from your
hard drive or CD player?

Doug

At 11/14/2003 01:22 PM, C Gauba wrote:

>For the past six months I have been using a new computer (an IBM Thinkpad
>notebook) which came with Windows XP (Home edition) pre-installed  A few
>days ago a problem developed with Windows Media Player (version 9, which
>also came pre-installed). It suddenly won't play ANY movie files, whether
>in MPEG/MPG or AVI format. In all cases the error message is the same: a
>pop-up windows says
>
>Error performing inpage operation.
>
>I get two choices, "close" or "Web help", the latter takes me (if I'm on
>line) to the Windows Media site which just says that no further help is
>available for my problem.
>
>The problem seems to be more than just Windows Media Player. I also have
>Irfan View (a great program) and this too doesn't work. I don't know if
>it's related but at about the same time my Adobe Acrobat 5.0 also failed
>and I had to reinstall (it now works, after reinstallation). My guess is
>some key file seems to have been destroyed, removed, or been damaged but I
>don't know how or which, or how to fix it.
>
>Need help to guide me in the right direction. I used to be comfortable in
>using - and fixing problems with - Windows 98 and before that Windows 95,
>but XP is new to me and I don't know where to begin.

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