When entering formulae into cells within a Table or Spreadsheet within Lt, it's important to note that minor differences between it and Excel Functionality can cause errors to appear if one is not careful.
The most common cause of the #FORM error (other than incorrect formula syntax) is hitting Return after entering the formula as you would normally do in Excel to 'apply' the formula. However, hitting Return in a cell within Lt will not apply the formula, it will create a new line within that cell:
In terms of the the formula syntax, Lt will read this as <Formula><Return>, which is not a valid formula (no formula has a Return at the end of it):