OK. I know what's happening, but I don't understand why your system is getting so upset.
Starting careers in 1944 and 1945 is only possible if you have the latest Flotilla mod or RUb (so I assume IUB) installed. This is mentioned in the readme.
If you don't have any of these mods installed, SH3Cmdr ordinarily doesn't care - details for the two years remain blank and are captured if you try to launch a career. For some reason though, your machine does care. I'll have a look at the code again and see what could be causing this - but the same code's been there since r2.0 and no-one else has raised this problem, nor have I seen it in testing.
Anyway, easiest fix is to d/l the Flotilla mod from
here. But read the readme first as it makes some other changes which you may not want! Or, simply avoid entering 1944/1945 years.