1) I know that there are some registration problems with the 64 bit CofePrev DLL. I have been unable to reproduce this myself, so far. Would you be willing to provide some feedback over private mail if I ask you for which keys do and do not exist on your machine?
2)
https://en.wikipedia.org/wiki/MS_Sans_Serif; use Helvetica or Arial. Default font in formatted is the default GUI font (set by Windows). I could change it to the default COFE flowsheet font (which since 3.1.0.4 is configurable) if you prefer this better. Note, you can paste rich text in this box, so you can format the text in any other application that is more suitable for .... formatting text instead of flowsheeting. I made the dialog larger and the font list wider (CUP)
3) TEA cannot tell you - does not even need to be in a unit. TEA is unaware of units. Apparently the unit deals with it, or the unit would fail. Please note that TEA and COCO as a whole ave been designed not only for simulation, but also for CAPE-OPEN testing. Hence it is once in a while a bit verbose with error and diagnostics info. In general, trouble-shoot a unit if it reports a failure. Note that during solve, COFE solves the log for each unit inside the solve log for the unit. If you must know whether it happened in a unit, save, rename to zip, unzip, find the message in the XML, see whether it is nested in a unit log.
4) Send me an example where it does not work well?
5) make it a bit bigger? The rich text box does the math behind the screen; screen fonts and printer fonts may differ a bit. If all fails, send me an example so that I can look at it.
6b) Depends. Where does the text come from? Are you pasting it from another application?
Are there any problems remaining that relate to solving a flowsheet?