Neue Version 6.0.91 (27.04.2016):
v6.0.91 - Fixed a bug in the Scenario Editor 'Swap' routines. All of these routines could possibly give an 'Error #5' response depending on what was being swapped. The swap was usually made but the error messages were off-putting to users. Hopefully this is all fixed now, sorry it took a while to find this one.