I just attempted the following in TestComplete 8.60 using JavaScript
function bladiddy()
{
var total = 123.456
total = Math.round(total)
Log.Message(total)
}
My log shows a value of 123 written to the log, no errors. Passing in a string, an empty string, a null all works just fine. If I include in the string non-numeric values, I don't get an error, but I get "NAN" in my log.
So, it might be helpful to understand what sort of error, problem, etc., you're getting. Could you put up the text of the error message(s) you're getting?