NIOS II IDE 7.1 SP1 error: Error accessing memory address

I am using NIOS II 7.1 SP1 IDE, I have been seeing this issue intermittently but today nothing will work and I can not use IDE to debug my software anymore :(.

When I go to debug the code, the it downloads and verifies correctly into SRAM but then I get the following message when I tries to start he processor.

Execution is suspended because of error

Warning:

Cannot insert breakpoint 1.

Error accessing memory address 0x580cbe0: Unknown error 4294967295.

I saw the same message last Friday but it was intermittent and I thought maybe I had damaged the board so I went to a known good board. I worked all week with the new board and everything was fine yesterday. I made minor changes to my NIOS code and the problem was intermittent. I came in this morning and the problem happens every time. I reverted back to known good code that worked earlier in the week but the problem persists. Out of desperation I rebooted my computer but that didn't help.

The board works fine when I download the code to flash and reboot (versus using IDE) and the sram passes diagnostics when the diagnostic image is loaded so I don’t believe there is a hardware problem. I just can’t get the IDE to work?

Could you point me in the right direction on how to root cause?

thanks,

Jennifer