an idea..

The arduino resetting is normal, its the tradeoff for the conveinece of the auto-reset used when uploading a sketch. Its Possible to hardware disable it (which also stops the auto reset working) and usually possible at the PC end to stop it toggling the DTR connection in software which then means the board doesn't reset. How its achieved on your particular setup will vary. Googling "Arduino disable auto-reset" and your operating system / application should yield some clues.