A number of people wrote to complain about ZeroBUGS not working properly, for example not stopping at main().
Guys, have you heard the phrase "the user is always wrong"? RTFM!
This is a known issue: http://www.zero-bugs.com/2.0/known_issues.html
as well as the wikipedia entry on VMware. You will find that "One must always rewrite; performing a simulation of the current program counter in the original location when necessary and (notably) remapping hardware code breakpoints".