[Zope] problem with python script

I am having a horrible time with a python script. The idea is to get a dollars-and-cents formatted string from the 3.87987234233e-1234 type string that the Sybase server is returning. The python script looks like this: --- final = (float(int(float(number[0:10]) * 100)) / 100) return final --- with one parameter (number) when I call it with either: <dtml-call expr="numberTrim(number=cur_bal)"> or <dtml-var expr="numberTrim(number=cur_bal)"> I get: Error Type: TypeError Error Value: unsliceable object if I use the "test" at the top and enter a value it works fine and if I hard code a value it works as well. The only time it WON'T work is when it's called with the cur_bal variable. Has anybody ran into this before? Thanks, Rick