600ex-rt & st-e3-rt help

I am using the above with a 7D in the manual mode, 1/250. I am getting a signal in the st-e3-rt after focuses is achieved, exclamation point and Tv .
After going through the manual a number of times I still can not understand what it is telling me. A simple explanation to put me on the right path would be a great help, thanks.

It's telling you that you're going beyond the effective sync speed. But I think you can just ignore it if your not getting any black bands on the side of the frame.

Older cameras supposedly drop one stop off sync speed when using radio communication.

It's Canons way of warning you that you may not get a perfectly sync'd image because you are exceeding their ability to develope a system that is not backwards compatible with their older DSLRs. Unless you are shooting white dry eraser boards the slight banding you will get is hardly noticeable at all. This has been discussed and demonstrated here in this forum and it is not a real issue.

Thanks for your reply's. I did ignore it and see no banding in the photos.
Thanks again