Unable to apply a fillet/Chamfer to the inside edge of a part.

[LandonUA9RC]

Hello, 
I am trying to fillet the inner edge of this part I designed and keep running into various errors. 

Error in bottom right, edge that I'm trying to chamfer or fillet is selected in the above photo.
I'm sure it has something to do with how many separate curves I used to outline the shape from the 3D scan, in which case I would appreciate some advice on A. How to fix my current file & B. How I would prevent myself from running into this error in the future. 
Please lmk if you need any more info.

Any advice or tips are welcome and appreciated, thanks in advance!

[davebYYPCU]

The selected curve, that involved the error is highlighted red.  Just happens to be adjacent to a mounting hole.  Until I review the file later, you may want to make the hole after the fillet/chamfer, in the timeline of operations. 

There will also be a relationship with the actual size of the proposed fillet/chamfer.

Might help….

[LandonUA9RC]

As a side note, for some reason I am unable to post in the English forums despite having no VPN, the website claiming I'm on the English version of the website, and my default language being set to english.

[LandonUA9RC · Accepted solution]

Issue fixed itself after a second look, false alarm. Sorry for the wasteful post, however I do still have that German issue if anyone has any ideas

(Fix was not forgetting to select the curve that was near the hole.)