READ not working

I am developing a windows dialog based program and have a problem with:

       num = GetDlgItemText(hwDlg, IDC_M1, myBuffer,20)
       If (num /= 0) Then
          iostatus = 1
          do while (iostatus /= 0)
             Read(myBuffer,*,iostat=iostatus) X
          end do

myBuffer = '25.6                  '
num = 4
and X = garbage
iostatus = 59

without the do while and the iostat, the program has a break at the read statement. When I programmed in C++, there was a lock function to keep myBuffer in real ,memory so the i/o works. This is part of a callback routine. What can I do to fix this?

Brooks