On Apache/2.0.46 Red Hat Enterprise Linux 3 (2.4 Kernel), I have no problem with this virtual host:

Listen 9285

<VirtualHost _default_:9285>

DocumentRoot "/var/www/arlington_donate/html"

<Directory "/var/www/arlington_donate/html">
Options +Includes
</Directory>

ScriptAlias /arlington_donate "/var/www/arlington_donate"

<Directory "/var/www/arlington_donate">
AllowOverride None
Options ExecCGI FollowSymLinks
Order allow,deny
Allow from all
</Directory>

</VirtualHost>

But on Apache/2.2.8 (Kubuntu 8.04 2.6 kernel)

I got this error:
[error] VirtualHost _default_:9285 -- mixing * ports and non-* ports with a NameVirtualHost address is not supported, proceeding with undefined results
...done.

Where should I begin looking to solve this problem?

Many thanks.

Debian and Ubuntu derivatives handle virtual host setup differently from Red Hat and other distributions. Look to the Kubuntu and Ubuntu site wikis and community documentation for information on using VirtualHost in Kubuntu.