I have a one project where CW10.6 will not produce a flash image. In C/C++ Build/Settings/Additional Tools I have "Create Flash Image" and "Print Size" both checked. Neither one of those two tools is invoked at the end of the link stage.
I have other CW10.6 projects where I have both tools checked and I get a size and hex (s-record) file.
I saw another posting about a similar issue in KDS where the author disabled parallel compile option and got his post build script running. I tried disabling the parallel build but it didn't help.