I will make more tests
When I do the tests
I add a code in the Init Event This.nInitDataSess = this.DataSessionId

o = createobject("class.dll")
=MyMethod()
? o.nInitDataSess && Gives 2
=MyMethod()
? o.nInitDataSess && Gives 3

But after you answer, which I guess you are correct
I test again and it gives 2 in the first and second run

Now after more testing, the error in Select 0 but for diffrent reason

Select 0
Use Mytable shared alias par && works
Select 0
Use Mytable shared alias par && Fails at second run

but

Use Mytable shared alias par && Works
Use Mytable shared alias par && Works
Use Mytable shared alias par && Works

Thanks for pointing it out.