Hi,
I've never seen that error message before, but one thing that looks weird is the "the_" at the beginning of the IP name, and the "_testbench" at the end of it.
I'd try deleting the nios2 processor from your qsys system, then re-adding it back again and see if that helps.
Also, you are connecting your nios processor's instruction bus to both an on-chip memory and a parallel port, but this is wrong. You should only be connecting the instruction master port to the on-chip memory. You should just be connecting the data master port to the parallel port if you want to access it.
Sahand
