I use the absolute path: D:\Program Files (x86)\Vim\vim73\gvim.exe, and I got the following error.

09:43:47, ERROR: Failed to save the source given by the server: Cannot run program "D:\Program" (in directory "E:\Topcoder.vimcoder\1708"): CreateProcess error=2, ϵͳÕҲ»µ½ָ¶

The default config doesn't work for me, too. (That's why I configure vimcoder myself)
But I can lauch gvim from my cmd. It has been added to PATH.

Thank you!