[Help] Use Jam STAPL Player to Update CPLD on Linux, but cannot update twice.

I want to update my CPLD program through the Jtag, which is just simulated with four pins of CPU. I write a linux driver to control the CPU pins, port the Jam STAPL Player to linux and compiled it as an application, now ,I can update my CPLD application use this way successfully, but when I finished to update the CPLD program , I can't repeat this process two times if not reboot my OS. When I do it the second time , the Jam STAPL Player print "Unrecognized Device ...". I dont know what's the trouble, can anyone help me ?
thanks!

maybe u can mail-to me: yuanyangliu258 at gmail dot com.