SQL 2008 SP2 RsClientPrint ActiveX - "Unable to load client print control"
Solution 1:
I also had the problem where users were being asked to install the ActiveX control every time they printed the report. This appears to be a problem peculiar to version 2007.100.1600.22 of the RsClientPrint addon.
Installing Cumulative Update 4 didn't update the version of RsClientPrint, so I replaced the 3 cab files with those from a 2008 R2 report server (v2009.100.160.1), deleted the rsclientprint.* files from the client machines and it all seems to work now.