Geometry in the bend region is too complex

Hi Guys,
I have made a simple rectangle Then I made flanges on all the four
sides and now I want to make four flanges along the new edges but I am
able to make only three flanges If I select the fourth side the error
in the headline appears.
I looked closure at the flange profile and it appeared to me that when
I was selecting the edge the profile created by solidworks was giving
it some extra length so that the flange was coming in contact with the
adjacent side and thats why it was not creating the flange.
Do u guys have any idea how to make it work. Again I made the flange
with bend position outside and it worked. Then I reduced the flange
length by editing the sketch and tried to change the bend position form
outside to material inside and again same error was coming.
Can u guys throw some light on this
Thanks in Advance
Vishal