Anyway bit the bullet and got myself a new HD 5670 to replace one of the 240's, so removed the troublesome app_info.
rev420 with OpenCL support just for your GPU.
Have installed rev.420 again, first UPDated Catalyst driver, installed SDK 2.1. After BOOT, get a message :card error? . No problems with MW on EAH 4850 (DP) and Collatz on EAH 4850 & HD 5770.(SP)(BTW GPUz, shows NO OpenCL!)
What is the 'safest FLOPS setting', I can use, with these cards, unfortunatly BOINC (6.10.56) shows 2 HD5770 1000 GFLOPS, each. But 5770 is > 1 TFLOP and 4850 =< 1 TFLOP.