Incredible. It apparently really was this litte "if" command that caused the crash!
Really, that never would have occured to me. Up to now, every map-edit I made (have done several map redesigns in the past) worked without problems without these commands.
Just bizarre...but well, I guess BF never stops surprising one, not even after years of modding

.
Really big thank you to you Tankerbot, for taking so much time (and brains

) to work this matter out with (or to be more precise: for) me and giving some very valuable tips. Saved me probably days and weeks of buggering and crashtesting until I'd have stumbled upon that.
EDIT: Oh yeah, and just so I can be the smartass once I want to answer to your rem comment "Also removed unneeded "zeros" from the end of some numbers.Unneeded data just drives me crazy."
Well, if you want to clean up proper, you could also have deleted some additional zeros.
E.g.
0.001 can always be written as .001
BF automatically reads that correctly.
.00xxx is used sometimes in Vanilla, but as usual, the devs weren't consistent in their coding...