In DIAdem 9.1 very few calc functions got text channel support. ChnMultipleSort was not part of it and unfortunatly no message appears. For compatibility it is the same in 10.1! We had to reprogram this function in a GPI DLL to get what we needed.
Matthias is insofar right as he said that DIAdem 9.1 doesn't sort text channels and that - unfortunately - there is no info message for that, but since DIAdem 10.0 the function "CHNMULTIPLESORT" works fine for text channels, too.