Unable to unbind NVR - Error 99 HELP?

Did you ever get this resolved?

I've bought the same NVR, the 4CH version, and have the exact same issue. I've upgraded to the latest firmware but cannot get it to unbind...

Any help would be much appreciated

DS-7604NI-K1 / 4P(B)
serial: 0420180913CCRRC51176227WCVU
Firmware: V4.30.097 build 240401

I had the same issue with the same NVR (DS-7604NI-K1 / 4P(B) ), when searching for this problem i came across this forum post.
Eventually i was able to work around it using an older version. I hope this works for you as well: