Problem with the function wip_bearerstart and wip_bearerstop

Hello everybody,

Why when I use the function wip_bearerStart don`t return me 0 as result but -27 and the start of bearer is correct because I can attach to GPRS.

Another question,
When I use the function wip_bearerStop, it functions correctly but when I write at+cgatt?, it returns me cgatt=1.