I have the same problem! Look at
here.
It seems a problem of Tiger. I don't know why...
I've tried a lot of different configuration, debug, statit, dynamic, disabled all the unncessary feature... No way of get it compile. I have the same error! My wx installation is fine, i have compiled few sample program using wxString, and all is working fine.
Somewere bethween November 2008 and Feb 2008 is changed, but i don't know what! (In Nov 2007 i have compiled a cvs version, and i'm still using that...)