MS VC 6 Internal Compiler Error using regex

From: the_dilster (dylan_at_[hidden])
Date: 2001-12-05 18:47:41

std::string pattern;
std::string line;
...
boost::regex expr(pattern);
boost::smatch what;
boost::regex_match(line, what, expr);

e:\boost_1_25_0\boost\regex\detail\regex_match.hpp(1053) : fatal 
error C1001: ININTERNAL COMPILER ERROR

VC 6.0 SP 5

Compiling in debug mode, no optimisations.

Tried using cmatch, line.c_str(), same thing.  
Put in 
#define BOOST_NO_MEMBER_TEMPLATES
before
#include "boost/regex.hpp"

and it worked, then took it out again and it worked again!
Deleting the obj file seems to work too...very strange.

Dylan