Re-enter the foreign tax credit interview. Skip thru the screens until you reach the screen header "Other deductions not definitely related".  There will be an amount you entered.

Click on the "Show relevant form" button at the bottom and it will show the entry on the f1116 wks. which then copied it to the f1116 form line 3b. If the amount and description are in error, you can delete it here, then finish skipping thru the interview to the end.

Form 1116 Copy 1 Part 1 3b entry is coming from Itemized Deductions entered. 

Click the link for more details about Entering Foreign Tax Paid in TurboTax.

Correction: The entry in f1116  3b came from the f1116 wks. In forms mode, bring up the f1116 wks. If the entry is in 3b(1), the source is from the 1040/1040S4 wks. line 22. If the entry is in either 3b(2) or 3b(3), then the source is from the screen described earlier.

I followed your directions and looked at  column (a) which is where the amount was showing. I tracked down the source location of the f1 116 3b column (a) entry. It was blank and that's whats odd about this. I went to all my 1099div sources and placed 0.00 in all the blank location to try to rectify it and that did not work either.

So after another 30 minutes of searching I right clicked on the (a) entry and there was an option to remove the entry.  It worked, the amount disappeared.  When I performed the smart check the error disappeared (which was to fill out another form of explanation).