After pulling my hair out attempting to figure out why password learning did not work, I looked at vchkpw.c to see what the problem was. It appears someone left a #ifdef FOOB write before password learning effectively disabling that feature. I simply removed the ifdef and recompiled and it worked. Just thought I should let someone know.
--- vchkpw.c-orig Tue Aug 5 15:55:53 2003 +++ vchkpw.c Tue Aug 5 16:04:03 2003 @@ -403,7 +403,6 @@ #endif -#ifdef FOOB #ifdef ENABLE_LEARN_PASSWORDS /* check for a valid vpopmail passwd field */ if ( vpw->pw_passwd==NULL||vpw->pw_passwd[0]==0) { @@ -420,7 +419,6 @@ TheName, IpAddr, LogLine); vchkpw_exit(15); } -#endif #endif