Calendar iCal export causing 500 internal error

• Error
• Feature request

When our users attempt run the Calendar export (either via tiki-calendar.php or tiki-calendar_params_ical.php) a 500 internal server error occurs.

From apache access.log:

10.100.44.149 - - [30/Apr/2010:07:33:27 -0400] "POST /eiadwiki/tiki-calendar_export_ical.php HTTP/1.1" 500 - "http://eiadwiki/eiadwiki/tiki-calendar_params_ical.php" "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3"

From PHP error log:
No error reported log.

HTTP Request:

POST /eiadwiki/tiki-calendar_export_ical.php HTTP/1.1
Host: eiadwiki
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Referer: http://eiadwiki/eiadwiki/tiki-calendar.php
Cookie: javascript_enabled=y; menu=@menu42__50%3Ac@menu42__600%3Ac@menu42__1050%3Ao@menu42__200%3Ac@menu42__350%3Ac@filtercal%3Ao@exportcal%3Ao; tab=1; activeTabseiadwiki%2Ftiki-adminusers.php=tab1; local_tz=AM; PHPSESSID=mkiu7d2r4jlj74f7hlt2brvvj4
Content-Type: application/x-www-form-urlencoded
Content-Length: 41

export=y&calendarIds%5B%5D=1&valid=Export

HTTP Response:

HTTP/1.0 500 Internal Server Error
Date: Fri, 30 Apr 2010 11:37:38 GMT
Server: Apache
X-Powered-By: PHP/5.3.2-dev
Expires: 0
Cache-Control: private
Pragma: dummy=bogus
Content-disposition: inline; filename=calendar.ics
Content-Length: 0
Content-Transfer-Encoding: quoted-printable
Connection: close
Content-Type: text/calendar; method=REQUEST; charset=iso-8859-15

We are running in a multi tiki environment on Windows Server 2003, tikwiki 3.2 and php 5.3.

This bug has been demonstrated on show2.tikiwiki.org

Please demonstrate your bug on show2.tikiwiki.org