diff --git a/twander.py b/twander.py
index 4e30f79..73e6986 100755
--- a/twander.py
+++ b/twander.py
@@ -6,7 +6,7 @@
 # Program Information
 
 PROGNAME = "twander"
-RCSID    = "$Id: twander.py,v 3.205 2006/12/18 17:35:09 tundra Exp $"
+RCSID    = "$Id: twander.py,v 3.206 2006/12/18 22:02:25 tundra Exp $"
 VERSION  = RCSID.split()[2]
 
 # Copyright Information
@@ -3572,7 +3572,9 @@
 
     elif (OSPLATFORM == 'win32') or (OSNAME == 'posix'):
 
-        usestartdir=False
+        # Find out if the OS thinks this is an executable file
+
+        executable = os.stat(selected)[ST_MODE] & (S_IXUSR|S_IXGRP|S_IXOTH)
 
         # Apply any relevant association information
         
@@ -3586,27 +3588,40 @@
         # association is defined, apply it to everything
         # except executable files.
 
-        if not assocfound and (ASSOCDFLT in UI.Associations) and not (os.stat(selected)[ST_MODE] & (S_IXUSR|S_IXGRP|S_IXOTH)):
+        if not assocfound and (ASSOCDFLT in UI.Associations) and not executable:
             selected = UI.Associations[ASSOCDFLT]
             assocfound = True
 
         
-        # If there is NOT an association, create absolute path to
-        # selected command
+        # In the case of Unix-like OSs, if the file is non-executable
+        # and has no association, this is an error and needs to
+        # flagged as such.  In Windows, this may- or may-not be an
+        # error because of Windows own association mechanism.  So, we
+        # pass the request through on Windows and let it handle this
+        # case.
 
-        if not assocfound:
-            selected = os.path.join(os.path.abspath(UI.CurrentDir), selected)
-
-            # Win32 has a special command interface wherein its internal associations
-            # are applied.  We only invoke command execution this way when twander
-            # found no associations of its own.
-
-            if OSPLATFORM == 'win32':
-                usestartdir=True
-
+        if not executable and not assocfound and OSNAME == 'posix':
+            ErrMsg(eBADEXEC % selected)
+            
         # Now execute the command
 
-        ExecuteCommand(selected, '', ResolveVars=True, ResolveBuiltIns=True, UseStartDir=usestartdir)
+        else:
+
+            usestartdir=False
+            # If there is NOT an association, create absolute path to
+            # selected command
+
+            if not assocfound:
+                selected = os.path.join(os.path.abspath(UI.CurrentDir), selected)
+
+                # Win32 has a special command interface wherein its internal associations
+                # are applied.  We only invoke command execution this way when twander
+                # found no associations of its own.
+
+                if OSPLATFORM == 'win32':
+                    usestartdir=True
+
+            ExecuteCommand(selected, '', ResolveVars=True, ResolveBuiltIns=True, UseStartDir=usestartdir)
 
     return 'break'