I am getting a "Check This Entry" on form 1116 to add a detailed explanation ... I am lost in translation here. What should I write?

Your Form 1116 Explanation Statement should include:

1. The foreign tax credit formula you used to calculate your foreign sourced US tax (Foreign Source Taxable Income ÷ Total Taxable Income Before Exemptions) x Total US Tax = Foreign Sourced US Tax), 
2. If you convert from foreign currency, attach a detailed explanation of how you figured the conversion rate, what dates you used and what converter you used. See IRS Form 1116, instructions, page 3, Foreign Currency Conversion.
3. Any other information that may help clarify the amounts on your Form 1116.