A workaround for users is to set 4th parameter to an empty string.

The problem is that headers is strstr()ed and otherwise used without checking to see if it is NULL.

I have modified the source for sendmail.c so that TSendMail looks like this:

int TSendMail(char *host, int *error, char *headers,
char *Subject, char *mailTo, char *data)
{
	int ret;
	char *RPath = NULL;
	TLS_VARS;

	if (headers == NULL)
		headers = "";

... other code unchanged ...

}

Also, the Ack() function can be cleaned up some more - I have done this but I don't know who to send my revised source to...