Help.

In ADE, an error started showing up in the calculator.  It keeps saying:  <Calculator>  Evaluation error(Cannot read waveform.  Shared Waveform token id(s) are null).  Expression: VT("I0/I11/net90")

As a result, I can't really use the calculator.

Obviously the last bit changes, depending on what I am trying to plot.  I never used to get this error, and I can't figure out what is wrong.  I tried erasing the simulation folder and the .artist_states, to see if something got corrupted.  It seems like many of the schematics are generating this errors (more than just one).

Any help is appreciated.

Ben