In one of my current project my team was facing problem in Reporting services viewer control. Some clients were getting "Unable to load client print control" and some were getting "Error loading resource library. (0x8007007E) and in some situation it was working perfectly alright. Based on individual cases we have resolved these issues by following instruction from the following links...
Error loading resource library. (0x8007007E)
Report Control SSRS "unable to load client print control"