[Asterisk-Users] fonction Getvar

[khady]

Hia ....
i try to use the fonction Getvar of asterisk to get a variable myDNIS
that i have define. i use it as follow
Action: Getvar
Channel: SIP...
Variable: myDNIS 

but asterisk don't know it .i have the response as follow
Response: Error
Message: Invalid/unknown command

does everybody meet this problem . i try all possible combination and
nothing
help please ..!! :-(
thanks in advance