Error 16882 Web Task not found

[2ni]

i try to run a web task i create in SQL 2000
it works when i write this :

EXEC sp_runwebtask N'CREATE_MAIL'

but if i want to specify the outputfile like this :

EXEC sp_runwebtask N'CREATE_MAIL', N'D:\mail2.eml'
or
EXEC sp_runwebtask 'CREATE_MAIL', 'D:\mail2.eml'
or
EXEC sp_runwebtask @procname=N'CREATE_MAIL', @outputfile=N'D:\mail2.eml'


SQL return me an error 16882 Web Task not found.
Someone can help me ??