This is from the MSDN documentation:
http://msdn.microsoft.com/en-us/library/vstudio/s5b150wd%28v=vs.100%29.aspx[
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'RFX_Long' : cannot convert parameter 3 from 'CString' to 'long &'
So what does this mean then? You obviously passed a parameter ( the third one) to RFX_Long and what you passed was of type CString, but a reference to a long was expexted plus there is no conversion possible from a CString to a reference to a long.
What exactly is a reference to a long?
Any legal expression allowed as the lefthand side of an assignment statement where the assigned part (righthand side) has the type long will do.
Cheers!