Josh W,
you're right. I've cleared the DllMain and I tested open/close teststand several times and the freezing is gone.
My mistake.
Thank you for clearing me on the Best Practices for Creating DLLs.
My best regards.
Daniel Coelho
VISToolkit - http://www.vistoolkit.com - Your Real Virtual Instrument Solution
Controlar - Electronica Industrial e Sistemas, Lda