Date parameter is not set CMD

gec

Hi

i have a batch file which calls report runner and creates my pdf reports. So far so good. But now i need to define three variables in the batch file (start time, end time and type of machine). I started only with start time and defined the PRF_TIMESTAMP (Using DB2 and TPC) parameter in birt and connected it to data set. The only problem is that when i run the batch file i get an error: PRF_TIMESTAMP parameter is not set!
Only if i set the default value in birt for PRF_TIMESTAMP, than i get my report. But the default value does not give me any good, cause i want to change my start date in batch file.

Any ideas?
I would appreciate it,
tnx
bye

GEC