I'm getting the same error message. I've double- and triple-checked my server settings, both remote and testing. Everything appears to be correct. I can connect to each just fine, but I get that error every time. I've tested the mysql connection in DW and it connects fine. I'm not sure what to do.
I'm using DW CS6 Mac, PowerCMS Builder, and connecting to godaddy.com (ugh, not by my choice)