multiple gpu OpenCL

Hi,
when I try to spawn multiple instances of GRTGen-OpenCL I get the Windows error message "The system cannot execute the specified program." on the second instance. Is there a way to get around this?
Michael
when I try to spawn multiple instances of GRTGen-OpenCL I get the Windows error message "The system cannot execute the specified program." on the second instance. Is there a way to get around this?
Michael