Hello.
Can you guess what particular action raises this error? E.g. rebuilding of a smart search index?
Could you please check for following setting in your web.config file, eventually try to set it to following (or higher) value:
<httpRuntime maxRequestLength="10000" executionTimeout="900"/>
(
http://msdn.microsoft.com/en-us/library/e1f13641.aspx)
Could you please also increase you connection string timeout?
<add name="CMSConnectionString" connectionString="Persist Security Info=False;database=;server=;user id=;password=;Current Language=English;Connection Timeout=240;"/>
Best Regards,
Radek Macalik