This the best link I have use to resolve the issue :http://www.dotnetnuke.com/Resources/Blogs/cid/153280/Sys-WebForms-PageRequestManagerParserErrorException.aspx
This issue shows when running reports with all parameters, there’s a security updates by Microsoft security update MS11-100 that restricts the amount of parameter for a single HTTP POST to 1000 see here
As suggested in the article, you can increase the parameter count by adding the below line in <appSettings> section increasing the parameter count to required.
<appSettings>
<add key="aspnet:MaxHttpCollectionKeys" value="2000"/>
</appSettings>
If SharePoint is in integration mode, we need to place the setting in the SharePoint web configuration.
Location: C:\inetpub\wwwroot\wss\VirtualDirectories\80
Save the file and Re-start IIS.