Steve Endow tracks down a connection provider issue associated with the econnect error “Run-time error 3265: Item cannot be found in the collection…”
eConnect Requester Crashes with “Run-time error 3265: Item cannot be found in the collection…” in Dynamics GP
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Archived post from 2010. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.