diff --git a/lib/agraph/scan.l b/lib/agraph/scan.l
index 4eabcdc..02eaaab 100644
--- a/lib/agraph/scan.l
+++ b/lib/agraph/scan.l
@@ -93,15 +93,26 @@ static void endstr_html(void) {
  * and report this to the user.
  */
 static int chkNum(void) {
-  unsigned char	c = (unsigned char)yytext[yyleng-1];   /* last character */
-  if (!isdigit(c) && (c != '.')) {  /* c is letter */
-	char	buf[BUFSIZ];
-	sprintf(buf,"badly formed number '%s' in line %d\n",yytext,line_num);
-    strcat (buf, "Splits into two name tokens");
-	agerror(AGERROR_SYNTAX,buf);
-    return 1;
-  }
-  else return 0;
+    unsigned char c = (unsigned char)yytext[yyleng-1];   /* last character */
+    if (!isdigit(c) && (c != '.')) {  /* c is letter */
+	unsigned char xbuf[BUFSIZ];
+	char buf[BUFSIZ];
+	agxbuf  xb;
+	char* fname;
+
+	agxbinit(&xb, BUFSIZ, xbuf);
+
+	agxbput(&xb,"syntax ambiguity - badly delimited number '");
+	agxbput(&xb,yytext);
+	sprintf(buf,"' in line %d", line_num);
+	agxbput(&xb,buf);
+	agxbput(&xb, " splits into two tokens\n");
+	agerror(AGERROR_SYNTAX,agxbuse(&xb));
+
+	agxbfree(&xb);
+	return 1;
+    }
+    else return 0;
 }
 
 /* The LETTER class below consists of ascii letters, underscore, all non-ascii