We recently had a problem in our test database with a large number of employees being placed in error status. The error message referred to a missing frequency - but it wasn't specific about which element (it would have helped a lot to know).
After a great deal of work, we found that there was a small number of employees for whom the error didn't appear and these turned out to be those who had a particular rate code entered in their compensation record.
It transpired that by adding the rate code, a frequency could be established by the payrun.
There are a few points to bear in mind:
A rate code element which has the eligibility of "eligibility group" rather than "payee" and appears in a section in the process list will be processed for every employee - this processing will effectively be "silent" for most employees if (as in this case) they don't have a corresponding rate code in compensation (the element resolution chain didn't help us here as the element in error didn't appear in most people's records). However, if a piece of data is missing - in this case the frequency on the HR rate code, it may cause an obscure and unexpected error for large numbers of employees