diff -uNr chemtool-1.6.11/main.c chemtool-1.6.11-new/main.c

--- chemtool-1.6.11/main.c	2007-08-26 14:49:26 +0300

+++ chemtool-1.6.11-new/main.c	2008-05-16 00:42:45 +0300

@@ -2938,7 +2938,7 @@

    or save operations as defined by the current i/o mode and displays error

    message dialog if necessary */

 {

-  int error;

+  int error, length;

   char errtext[255];

   char oldname[512];

   char *tempstr;

@@ -2950,6 +2950,23 @@

   strcpy (oldname, filename);

   strcpy (filename,

 	  gtk_file_selection_get_filename (GTK_FILE_SELECTION (fs)));

+

+  while ((length = strlen(filename)) > 507 )

+  {

+    snprintf (errtext, 255, "Input filename %s contains %d\r characters and this too long.\n", filename, strlen(filename));

+    gtk_label_set_text (GTK_LABEL (message), errtext);

+    gtk_widget_show (messagew);

+    gtk_grab_add (messagew);

+    strcpy (filename, oldname);

+    snprintf (errtext,255, "Chemtool 1.6.11");

+    gtk_window_set_title (GTK_WINDOW (window), errtext);

+	

+    return;

+  }

+    

+    if (strstr(filename, ".cht") == NULL)    

+	strcat(filename, ".cht");

+	  

   if (datadir == NULL || (int)strlen (datadir) == 0)

     {

       tempstr = strrchr (filename, '/');