I have found the soloution of this issues
Basically these specific words like (“Z”, 1, 0 8, 9 ) do not contain in Challenge and Response code.
These numbers are getting confused with the following numbers like Number '8' being confused with the letter 'B', Number '0' being confused with the letter 'O', Number '1' being confused with the letter 'I' etc. However in order to go more details could you provide us the screen shot of the challenge code.
For more information you can refer the McAfee KB Article KB72776 .