There IS a mismatch between the nic and the switch. I wouldn't think that this would cause a problem. Do you think this could be the problem?
Yes, I am quite sure that's exactly the problem because that is the way we have finally been able to reproduce the problem here. (I know it shouldn't be a problem and we are trying to solve it in the software). If you can change the switch to a 1Gb one or connect both computers directly without switches in between probably you won't have more problems.
Have you been on holiday? Why no responses from Next Limit Tech support for a month?
No I have not been on holiday, but we have had problems with our mail servers and may be some e-mail got lost. Sorry for that