input conversion error



Dear all;

Would you please tell me the reason of the following error?
forrtl: severe (64): input conversion error, unit 68, file /home/
mirjani/Fortran/Mmn-inside/fort.68
Image PC Routine Line Source
wannier.exe 080B5CA7 Unknown Unknown Unknown
wannier.exe 080B52C7 Unknown Unknown Unknown
wannier.exe 08070C6A Unknown Unknown Unknown
wannier.exe 08050CB4 Unknown Unknown Unknown
wannier.exe 0805094F Unknown Unknown Unknown
wannier.exe 0805D3CD Unknown Unknown Unknown
wannier.exe 0805B647 Unknown Unknown Unknown
wannier.exe 0804D6AF Unknown Unknown Unknown
wannier.exe 08049F81 Unknown Unknown Unknown
libc.so.6 009FDDE6 Unknown Unknown Unknown
wannier.exe 08049EC1 Unknown Unknown Unknown

Thanks in advance,
Fatemeh
.