1.7.9 Incompatible but will not switch to 1.7.5 etc

Hi,

I am having problems with changing the 1.7.9 to 1.7.5 so that it'd work for whitelisting etc. However every time I install, change, or whatever to get it to 1.7.5 it immediately goes to 1.7.9 INCOMPATIBLE. How come I cant get it switch? Or should this have no effect on me being able to create my server? Its taking a ridiculous amount of time to turn "online."

Thanks