You might take a look at how Pololu engineers configure the Wixel, which uses essentially the same chip. The source code is available for various preprogrammed applications and in it, the authors comment on the occasional strange and/or unexpected behavior of the radio. http://www.pololu.com/catalog/product/1336
I don’t like the restricted IAR development system that TI provides and suggest that you consider experimenting with Wixels and the unrestricted, free Eclipse/SDCC package instead. It is a lot cheaper to go that way than TI’s dev kits, and you get the USB version of the CC2510 as well. Finally, Pololu engineers are happy to help developers work with their products!