As an update to the above, I was able to get the report to run, but the problem recurs sporatically.
In my test report template, I am prompting to enter two dates - a beginning and end date range.
After acknowledging the "Missing ParameterField current value" error, I was taken back to the parameter entry boxes. Attempting to re-submit the same values resulted in the same error again. Changing the values to something different would often (but not always) run the report to completion.
I have not been able to find a particular pattern to the rejection. Sometimes they run from the first entry, but once rejected it seems that they have to be changed to something else in order to get the report to run. Changing one variable only will error and return the report to a prompt showing the un-changed variable, which has to be changed in order to successfully run the report. Attempting to re-enter the original value does not overcome the error.
Since the report DOES run, I'm guessing it must have to do with how the inputted parameter variables are being passed (or not being passed), and somehow changing them after the initial rejection seems to overcome the problem, temporarily at least.
Which I can deal with, but it leads to angst and confusion and time wasted among the target users of the reports for whom this is supposed to simplify their lives, not make it more complicated if they have to continually jigger the parameter values in order to get the report to run.
There must be an identifiable reason and solution for this. I can't believe Alan and I are the first to come across this issue.