mistake with piega (bend)

[ele5]

Bye to all,
I got this problem, using the fold(bend) command to theok opened a window saying:
fold(bend):impossible to create fold(bend).
no corresponding face has been found.

What should I do to create the fold?
Thank you.

 

[rf.infissi@libero.it]

try to better describe the sheet to fold

 

[ele5]

at this time the problem gives me it on a tub with the four sides and a handle (so a double bending on one side). where there are the drains does not radiate with fold(bend).
the same happened on a triangle with two folded legs of which one at 45°

 

[rf.infissi@libero.it]

try to extrude the face where to bend the value of the fold radius seems to me and then bend