I use WinGDI version.
Latest working nightly is r.5645 (April 20th), file size is 3.03 MB and it works correctly.
Newer nightlies r.5660 (April 24th) and r.5662 (April 26th) have a smaller size (2.45 MB) and return this error:
(http://i47.tinypic.com/2uhvb0h.png)
Same for me on sdl win version, this error is reported:
The program can't start because libgcc_s_sjlj-1.dll is missing
This Problem was Reportet in the German Forum.
http://www.simutrans-forum.de/forum/thread.php?threadid=7024 (http://www.simutrans-forum.de/forum/thread.php?threadid=7024)
The nightly server compiled Simutrans without static linking. Werniman is confident that he solve the problem and the next nightly will work again.