The components of a MAC address, when expressed as a group of six octet values, are expressed as hexadecimal values (eg. FE:DC:BA:01:23:45) - Your code does not account for this with the maximal octet value of 99 (decimal) provided by your code.
in reply to Re: How to increment a MAC Address?
in thread How to increment a MAC Address?
Although in stating this, I should note that this is a problem too with the problem description in the original thread post.
perl -le "print unpack'N', pack'B32', '00000000000000000000001000000000'"