GH tester error

I am facing this error while executing the GH Test. Is this any installation error or some other kind of error? Can you help me out?

[ 2012/06/26] [Infrastructure] Subscribe:“OUTPUTXY” to service “ABCservice” using schema “schemaxyz” timeout 5000ms via “webMethods Integration Server Domain” Fatal error: Cannot subscribe to " webMethods Integration Server" Could not reach GH Tester at: http://
java.lang.IllegalArgumentException: Could not reach GH Tester at: http://
[ 2012/06/26] [Failed] 1 iteration completed, 1 iteration failed (1)
Logging summary: Info (0), Warnings (0), Errors (0)
Overall status: Failed