Executing a Stored procedure in powerscript

DECLARE AddUserToPool PROCEDURE FOR circorfo.addusertopool    newuser = remoteuser  ;

int rowsel = 0;
string remoteuser = "";

rowsel = dw_remoteuser.GetSelectedRow(0);
remoteuser = dw_remoteuser.GetItemString(rowsel,"user_name");

EXECUTE AddUserToPool();

In the above script I am getting a Syntax error on the execute statement.  From the documentation this appears to be correct syntax.

What am I missing here.

Also the SP take a string input of the user name.  I extract this username form a datawindow and than want to pass that name to the SP.

Is the method above the correct way of doing that?

Thanks

TPS