Ciao bradyw,
if you want to embed code in in IP template, it must run in "full-trust" mode.
This is due to the fact that code is potentially dangerous.
That's why you cannot publish the form as is to a server running Forms Services.
If you wish to use your form via browser, you need to ensure the security level (Form Options) is set to full-trust and (but this is the only option you will be presented) publish the form as an administrator-approved template.
The file you will be publishing must be uploaded into Forms Services (via Central Administration, Manage Form Templates) and subsequently deployed to the site collection where you need it to be available.
This configuration can only be done by a farm administrator.
HTH
Ciao
Claudio Brotto
MCP, MCAD.NET, MSSD.NET, MCTS SharePoint, MCT
http://blogs.devleap.com/devlizard