diff --git a/tren.py b/tren.py
index 9824e30..797e922 100755
--- a/tren.py
+++ b/tren.py
@@ -9,7 +9,7 @@
 BASENAME = PROGNAME.split(".py")[0]
 PROGENV  = BASENAME.upper()
 INCLENV  = PROGENV + "INCL"
-RCSID = "$Id: tren.py,v 1.231 2010/08/26 18:50:09 tundra Exp $"
+RCSID = "$Id: tren.py,v 1.232 2010/08/27 15:28:55 tundra Exp $"
 VERSION = RCSID.split()[2]
 
 # Copyright Information
@@ -953,6 +953,7 @@
 
                 lname = ""
                 rname = ""
+                newname = ""
                 tstart = renrequest[TARGETSTART]
                 tend   = renrequest[TARGETEND]
 
@@ -968,45 +969,53 @@
                     tend = len(name)
                     
                 if tstart or tend:
-                    
+
+                    bound = len(name)
+                        
+                    # Normalize negative refs so we can use consistent
+                    # logic below
+
+                    if tstart < 0:
+                        tstart = bound + tstart
+
+                    if (tend != SINGLEINST and tend < 0):
+                        tend = bound + tend
+
+                    if tstart > tend:
+                        ErrorMsg(eBADSLICE % "%d:%d" % (renrequest[TARGETSTART], renrequest[TARGETEND]))
+
+
                     # Condition and bounds check the target range as needed
 
                     # Handle single position references
                     if (tend == SINGLEINST):
 
-                        # Compute bounds for positive and negative
-                        # indicies.  This is necessary because positive
-                        # indicies are 0-based, but negative indicies
-                        # start at -1.
-
-                        bound = len(name)
-                        if tstart < 0:
-                            bound += 1
-
                         # Select the desired position.  Notice that
-                        # out-of-bounds references are ignored.  This is
-                        # so the user can specify renaming operations on
-                        # file names of varying lengths and have them
-                        # apply only to those files long enough to
-                        # accommodate the request without blowing up on
-                        # the ones that are not long enough.
+                        # out-of-bounds references are ignored and the
+                        # name is left untouched.  This is so the user
+                        # can specify renaming operations on file
+                        # names of varying lengths and have them apply
+                        # only to those files long enough to
+                        # accommodate the request without blowing up
+                        # on the ones that are not long enough.
 
-                        if abs(tstart) < bound:
+                        if 0 <= tstart < bound:
                             lname, name, rname = name[:tstart], name[tstart], name[tstart+1:]
 
+                        # Reference is out of bounds - leave name untouched
+
+                        else:
+                            lname, name, rname = name, "", ""
+
                     # Handle slice range requests
 
                     else:
                         lname, name, rname = name[:tstart], name[tstart:tend], name[tend:]
                     
 
-                # Save current state of name
-                        
-                newname = name
-                    
                 # Handle conventional string replacement renaming requests
 
-                if renrequest[OLD] or renrequest[NEW]:
+                if name and (renrequest[OLD] or renrequest[NEW]):
 
                     # Resolve any embedded renaming tokens