Trying to explode...says it's undefined

[ianevans]

PHP4.0.2
FreeBSD
Apache

I'm trying to explode a date string like:
2001-05-28

Here's the code:

$date_elements = explode("-", $date);
$date = mktime(0,0,0,$date_elements[1],$date_elements[2],$date_elements[0]);

I'm getting the following error:

Fatal error: Call to undefined function: explode()

If explode is in both PHP3 and PHP4, how the heck can it be undefined?

After a nice quiet day of coding this one is putting a nice forehead shaped dent in my desk.

Thanks!