symple programming task

[Ivan Ivanivich]

hi all, i have simple programming task:

[quot]
If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.

Find the sum of all the multiples of 3 or 5 below 1000.
[/quote]

this task from http://projecteuler.net/ site

I wrote a solution in python

http://pastebin.com/QXtNuRWU

this script returned correctly result if "basis < 10", but if "basis < 1000" result is 266333 and it is not correctly answer on site http://projecteuler.net

it is my script problem or site not working correctly?

thanks

sorry for my english