Question: I'm trying to remove dollar signs and commas from my form input (for example, $1,000.00 => 1000.00)

I have the following following line in my before\_validation method in my model:

```
self.parents_mortgage = self.parents_mortgage.to_s.gsub!('$,','').to_i

```

This is causing any number to be put through to zero out. Is there something wrong with my syntax?

Answer: 
Is it possible there's a little bitty bit of whitespace outside of the PHP tags in blabla.php line 581? I bet there is.

See, if you have **anything** outside of PHP tags, that is sent to the browser. And once something has been sent to the browser, you can't send headers (like the sessionID cookies!) anymore.

The problem is likely not XAMPP, but your PHP code as you put it on the flash drive.
The error states: `output started at /path/to/geeklog/public_html/blabla.php:581`, so I would start there. You need to send all headers before outputting anything, this includes whitespace as mentioned by others here.