--- a/src/tkgate/block.c.orig	2012-07-30 18:49:30.370000001 +0200
+++ a/src/tkgate/block.c	2012-07-30 18:51:02.209000052 +0200
@@ -908,7 +908,7 @@
 	char buf2[STRMAX];
 	strcpy(buf2,value+1);
 	buf2[l-2] = 0;
-	sprintf(buf,quoteChars(buf,buf2,"\"\\"));
+	sprintf(buf,"%s",quoteChars(buf,buf2,"\"\\"));
 	fprintf(f,"\"%s\"",buf);
       } else
 	fprintf(f,"\"%s\"",quoteChars(buf,value,"\"\\"));
--- a/src/tkgate/expr.c.orig	2012-07-30 18:59:20.786000001 +0200
+++ a/src/tkgate/expr.c	2012-07-30 19:01:24.208000347 +0200
@@ -497,7 +497,7 @@
     if (l < 0) return -1;
     s += l; n -= l;
     if (n < 4) return -1;
-    s += sprintf("%s",findSymbol(e->op));n -= strlen(s);
+    s += sprintf("%s","%s",findSymbol(e->op));n -= strlen(s);
     l = Expr_sprint(s,n,e->r);
     if (l < 0) return -1;
     s += l; n -= l;