Just upgraded to ES 9.6.100 and the Pre Check Writing report will not run.
Error message is
this Field name is not known
Details: errorKink
Error in File MACAPPRECHK
error in formula F_DiscToTeTaken:
// determine if discount is still available

Does not give field name

We had similar problem after updating to ES 9.6.100. Found that we had customized the macapprechk report in crystal version 11. This causes issues, we needed to change the custom database connection, re-map fields, and fix a few formulas before getting it to work.

See Document: 23.709.392 - Macola ES version ES9.5.800 - Changing the Custom Database Connection for Crystal Reports

Good luck.