--- htk_3.4.1/HTKLib/HModel.c	2009-03-12 18:46:34.000000000 +0000
+++ htk_3.4.2/HTKLib/HModel.c	2009-11-28 14:25:53.578000000 +0000
@@ -4488,12 +4488,12 @@
   Boolean isPipe;
   FILE *f=NULL;
 
-  if ((fname==NULL) || ((f=FOpen(fname,NoFilter,&isPipe)) == NULL)) {
+  if ((fname==NULL) || ((f=FOpen(fname,HMMDefFilter,&isPipe)) == NULL)) {
     if ((trace&T_XFD) && (fname!=NULL))
       HRError(7010,"InitXFormScanner: Cannot open source file %s",fname);
     p = xformDirNames;
     while ((p!=NULL) && 
-	   ((f=FOpen(MakeFN(macroname,p->dirName,NULL,buf),NoFilter,&isPipe)) == NULL)) {
+	   ((f=FOpen(MakeFN(macroname,p->dirName,NULL,buf),HMMDefFilter,&isPipe)) == NULL)) {
       if (trace&T_XFD) 
 	HRError(7010,"InitXFormScanner: Cannot open source file %s",buf);
       p = p->next;
--- htk_3.4.1/HTKLib/HShell.h	2009-03-12 18:48:12.000000000 +0000
+++ htk_3.4.2/HTKLib/HShell.h	2009-11-28 14:28:29.161000000 +0000
@@ -48,6 +48,7 @@
 #include <time.h>
 #include <Winsock2.h>
 #else
+#include <sys/wait.h>
 #include <sys/time.h>
 #endif
 #include <errno.h>
--- htk_3.4.1/HTKLib/HShell.c	2009-03-12 18:48:03.000000000 +0000
+++ htk_3.4.2/HTKLib/HShell.c	2009-11-28 14:31:47.749000000 +0000
@@ -919,6 +919,7 @@
 #ifdef WIN32
 #define popen _popen
 #define pclose _pclose
+#define WEXITSTATUS(status) (status)
 #endif
 
 /* EXPORT->FOpen: return either a file or a pipe */
@@ -941,6 +942,10 @@
    if (FilterSet(filter,cmd)){
       SubstFName(fname,cmd);
       f = (FILE *)popen(cmd,mode);
+      if (WEXITSTATUS(pclose(f)) != 0)
+	f = NULL;
+      else
+	f = (FILE *)popen(cmd,mode);
       *isPipe = TRUE;
       if (trace&T_IOP)
          printf("HShell: FOpen - file %s %s pipe %s\n",