Error: 'this.appearingFX' is null or not an object

[gmolish]

What steps will reproduce the problem?

1. In IE 7 I am serving an asp.net page. When the page initially loads the
   tool tips work as expected. When I select a page filter that trims down the
   results of the page I get the error message mentioned above.

What is the expected output? What do you see instead?
Expected output is the cooltip. Instead I see nothing.

What version of the product are you using? On what operating system?
I am using the latest version as of 1/11/2010. I have IIS 7 running on
Windows 2008 server.

[okonet]

Please check the dependent libraries (prototype & effects.js)

[gmolish]

Both prototype.js and effects.js were updated to the latest versions. I believe this error is unique to asp.net auto postback. It appears to be working fine everywhere else (when no postback is involved). I've gone with a pure css solution since I couldn't find a way to make it work with an asp.net page that involved auto postback. Thanks for your response.