COM+ getObject fails

hi to all
I hv main functions under that i am calling another function to execute another routine. when function 2 fails i am sending the return values="Fails". But function 1 routine has commited.

let me explain u Clearly.
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Public function MainFun()
On Error goto ErrHand
CNN=Open Connection
Inserting method Cmd Object using Stored Procedure

result=call SubFunction (CNN)

if Reult="Fail"
goto ErrorHand
endif

getObjectcontext.Setcomplete
MainFun="success"

exit function

ErrHand:
getObjectcontext.SetAbart
MainFun="Fails in error"
end Function


Private function SubFunction ( getCon )
On error goto abc
Insert ing in Table use Cmd Object ( using Stored Procedure)
Exit function
abc:
SubFunction ="Fails"
End Function
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in Sp i am not using any beging and commint Trnsactions

In Sufunction fails Mainfunction has to rolleback But it is not rollebacking.

why???????