ADO error - Append method

Hello!

I have the error below. I've seen many people have this error but I didn't find an explanation.

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This message is for C/AL programmers:

An exception was raised in method Append. The OLE control or Automation server has returned error (HRESULT) -2147352567.
The component did not provide the exception description.

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Using the debugger, it stops here:

cmd.Parameters.Append(prm1);

where:
cmd - automation 'Microsoft ActiveX Data Objects 2.7 Library'.Command
prm1 - automation 'Microsoft ActiveX Data Objects 2.7 Library'.Parameter

prm1 is being initialized this way:

prm1:=cmd.CreateParameter('UserID', 200, 1, 20, USERID);

The interesting thing is that sometimes it works, sometimes it doesn't. And I can't find the catch.

I use NAV 4.0 SP2, SQL Server 2000.

Thanks!