This question would be easier to answer if we were to see what got put into Label2.Text
From the error message, under extreme magnification, I see the inputs to the multiplication as ""260"" and "1"
That double double quote sequence looks fatal to math blocks.
Use the replace text block to change all " to the empty text block, on the way into the * math block.
Here's an inline procedure for that:
(draggable)
The + 0 was needed to prove the result was a number and to force it into a numeric type internally.