Problem with COM port and local objects

[Blacks85]

Hello,

i am programming with MVS2008 in vb.net for windows ce 6.0 - framework 3.5

I have an issue with the following code:

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REFRESH SUB (byval myVar as pl30message)

AggiornaTim.Enabled = False
Debug.WriteLine("myVar")


If Not myVar.isOnlineIgnoreWeight Then CaricaPesoInButton(OnlineBtnPeso,myVar)

AggiornaTim.Enabled = true
END SUB

CaricaPesoInButton(byref tmpButton as button, byval myVar as pl30messagge)

debug.writeline("myVar")

END SUB
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AggiornaTim is my timer, 300 ms
myVar is the problem
The only "caller" of REFRESH sub is timer event, i disable it right after enter in the sub

How is possible that myVar is different in the two debug.write ?