Error: Flash Downloader failed – “Cortex M3”

Hello,

I‘m trying to evaluate Keil Embedded Workbench.

I used an STM32 and Kinetis Eval Board with a Segger J-LINK Debugger. On Both I get the Error when I try to Flash the Code (Compiling went without Errors): Error: Flash Downloader failed – “Cortex M3”

The Eval-Boards and the Debugger are working fine with IAR and Rowley Crossworks, so it must be something with Keil.

Any Idea what I could do to avoid the error?

Thanks and regards