2008 R2 terminal not redirecting printers

I have five Virtual 2008 R2 terminal servers and one Virtual broker server managing client connections using DNS round robin. At any given time I have 100-125 concurrent client connections connected to the farm. The client connections consist of 30-40% remote clients connecting via VPN using Easy print to print back to they're local default printer on their PC and a mix of local thin clients running Win 7 & XP and . I have 54 department printers configured on each terminal server as local devices. When a thin client connects via RDP, a logon script runs which looks at the local device name and assigns the appropriate default printer. I frequently get complaints that the printers aren't showing up in a user session, then the user doesn't have access to the printer they should be getting re-directed to. I keep getting many Event ID 318 Source PrintService - Failed to upgrade printer setting settings for printer... And Event ID 7011 source - Serivce Control Manager - Timeout for UmRDP Service, WPDBusenum Service, VxSms service, Audioendpoint Builder, Netman. These erros are occurring on all terminal servers.