HiCould any one inform me why the cdu misprints various numbers such as 0 when typed it changes into 8 thanks in advanceDave

Because the screen ratio and resolution you are using on your monitor was not common when the program was written. The solution is to stretch the FMC until this doesnt happen anymore.

See also the pmdg knowledge base: http://support.precisionmanuals.com/KB/a66/fmc-buttons-do-not-operate-the-correct-keys.aspx