Error while mail design replace

Dear Friendswhen i replace multiple users using text file through server program in notes 5.0.11 for example:

program : nconvert

command line : -f c:\temp\test.txt Std* mail50.ntf

then it gives error message

Running Program document for ‘nconvert -f c:\temp\test.txt Std* mail50.ntf’

Mail Conversion Utility starting

Mail Convert Failed: None of the specified databases’ templates match ‘Std*’

Mail Conversion Utility shutdown

the test.txt file contains multiple users mail files with path (mail\abc.nsf, mail\cdf.nsf etc.)

when i give

program : nconvert

command line : mail\abc.nsf Std* mail50.ntf

then it replaces design

what could be the problem. Pl explain.

thanks

deepak