The error code is caused by using commas in the LEFT
function where semicolons are needed (OpenOffice requires semicolons in most places that Excel uses commas).
In addition, as pointed out in the comments to this question, OpenOffice sees a number with currency formatting as just a number and the LEFT
function will only return numbers from that cell.
To work around this, use Text to Columns to convert all currency numbers to text. Either on the original data, or on a copy in another column or sheet if you need to maintain the formatting as numbers on the original.
Highlight all the currency cells you are going to convert to text. Select Data→Text to Columns. At the bottom of the popup window, click on the column of cells you are converting to highlight them. Select column type "Text". Repeat if you are converting multiple columns. Click the OK button to perform the conversion.
Now your original formula will give a new error code because it objects to doing math on a text string. To fix this use the function VALUE
to convert back to a number where necessary:
=IF(LEFT(D12; 1)="$";VALUE(D12)*Conversions.C4;IF(LEFT(D12; 1) = "€";VALUE(D12)*Conversions.B4; D12))