What version of the DNG converter are you using?
It has to be the equivalent level to the Adobe Camera Raw version that would be needed for that camera, ie 5.4 or higher.
You can get it here: http://www.adobe.com/support/downloads/detail.jsp?ftpID=4578
I saw where I needed version, 5.4, except doesn't that version only work with CS4? I was under the impression the highest version usable on CS3 was 4.6, which as I stated gave me error messages.
The DNG converter is a standalone application. We are not talking about the ACR plug-in for Photoshop.
The converter will make your T1i raw files usable in Photoshop.
OMG so easy. Thanks so much. My daughter is taking a high school photography class, and she is insistant that everything must be RAW and done within photoshop, so this will enable her to complete her work at home.
Glad it helped and good luck for her in the class.