Ok try using '0.##' instead. Then you'll at least get a 0 returned. With only #s it doesn't bother to hold the value and you end up with a 0 length string.

You know what the difference between using the 0 and # characters are right? # doesn't care if there are values that remain there. 0 makes sure that a a value of 0 is there in the string.

So...
[pascal]StrToFloat(FormatFloat('0.##', 0.00));[/pascal]
will return 0. No errors, one line.