diff --git a/tools/tiff2pdf.c b/tools/tiff2pdf.c
index fe8a6ea..b7b4b01 100644
--- a/tools/tiff2pdf.c
+++ b/tools/tiff2pdf.c
@@ -747,7 +747,7 @@ int main(int argc, char** argv){
 	/*
 	 * Input
 	 */
-	if(argc > optind) {
+	if(argv && (argc > optind)) {
 		input = TIFFOpen(argv[optind++], "r");
 		if (input==NULL) {
 			TIFFError(TIFF2PDF_MODULE, 
diff --git a/tools/tiff2ps.c b/tools/tiff2ps.c
index 82a5d84..3563f30 100644
--- a/tools/tiff2ps.c
+++ b/tools/tiff2ps.c
@@ -2964,7 +2964,9 @@ tsize_t Ascii85EncodeBlock( uint8 * ascii85_p, unsigned f_eod, const uint8 * raw
     
             if ( val32 == 0 )                   /* Special case */
             {
-                ascii85_p[ascii85_l] = 'z';
+                if(ascii85_p != NULL) {
+                    ascii85_p[ascii85_l] = 'z';
+                }
                 rc = 1;
             }
     
diff --git a/tools/tiffcrop.c b/tools/tiffcrop.c
index 722b132..470a18d 100644
--- a/tools/tiffcrop.c
+++ b/tools/tiffcrop.c
@@ -958,7 +958,6 @@ static int readContigTilesIntoBuffer (TIFF* in, uint8* buf,
 		     return 1;
 	    }
           }
-        prev_trailing_bits += trailing_bits;
         /* if (prev_trailing_bits > 7) */
 	/*   prev_trailing_bits-= 8; */
 	}