Additional error checking.
diff --git a/ms/do_fips.bat b/ms/do_fips.bat
index a78fc25..3b0d2aa 100644
--- a/ms/do_fips.bat
+++ b/ms/do_fips.bat
@@ -56,7 +56,9 @@
 @if ERRORLEVEL 1 goto error
 
 nmake -f ms\ntdll.mak clean
+@if ERRORLEVEL 1 goto error
 nmake -f ms\ntdll.mak
+@if ERRORLEVEL 1 goto error
 nmake -f ms\ntdll.mak install
 @if ERRORLEVEL 1 goto error
 
diff --git a/util/fipsas.pl b/util/fipsas.pl
index 6e10d7d..fc2a759 100644
--- a/util/fipsas.pl
+++ b/util/fipsas.pl
@@ -49,11 +49,11 @@
 my ($from, $to);
 
 #rename target temporarily
-rename($target, "tmptarg.s") || die "Can't rename $target\n";
+rename($target, "tmptarg.s") || die "Can't rename $target";
 
 #edit target
-open IN,"tmptarg.s";
-open OUT, ">$target";
+open(IN,"tmptarg.s") || die "Can't open temporary file";
+open(OUT, ">$target") || die "Can't open output file $target";
 
 while (<IN>)
 {