http://groups.google.com/group/web2py/browse_thread/thread/efdb2e4c5f3eda26

VERSION

@@ -1 +1 @@
-Version 1.99.3 (2011-11-23 17:29:51) dev
+Version 1.99.3 (2011-11-23 23:04:18) dev

gluon/dal.py

@@ -5591,7 +5591,8 @@ class Field(Expression):
             dest_file = open(pathfilename, 'wb')
             try:
                 shutil.copyfileobj(file, dest_file)
-            finally:
+            except IOError:
+                raise IOError, 'Unable to store file "%s" because invalid permissions, readonly file system, or filename too long' % pathfilename
             dest_file.close()
         return newfilename