meh...
Try this:
Right click on your MapleStory.exe in your v88 folder and select properties. Once in the properties, click on the compatibility tab, check the box that says run this program in compatibility mode for: select Windows XP (Service Pack 2) from the drop down menu and click Apply. (You can also try the other choices and see if it works...)
If that doesnt work, then if/when your computer prompts you with a message saying that MapleStory and the Windows 7 operating system have some known compatibility issues, you get a choice to look for solutions online or run program. Click run program, and this should allow you to play SoulMS. Note that this solution might not work...