SSRS returns The status code returned from the server was: 12002

i have a report which executes about 2 hours, and after about 1 hour of execution i see that error, at the top of the page.. And i have complex structure of app: firstly i use data extension to calculate datasets in the report (but everything is fine there, and if i execute report without SSRS using that methods, it returns result),secondly i have web service which translates ssrs page to the user. I turned off execution timeout of SSRS. Also i added httpRuntime element with maxRequestLength="1000000" and executionTimeout="1000000" to web.configs of report server, report manager and my web service.. But nothing is changed. If report executes less time, then everything is ok.. That problem occurs only if report is executing more then 1 hour.

Forgot, i use IE9 to view report.