There could be a few possiblity.
1. You are using features not supported by infopath 2003, as this version was probably the first version so it lacked a lot of features.
2. You might have multiple views (but from what you said it's the active view so, i doubt it).
3. Compatibility issue with the form controls, some controls cannot be rendered unless the other user also has the same info path version installed.
Also you shouldn't have to create a submit button as the form will generate one if you set it to submit to an email address or group.
It's probably best to check which the online documentations for compatibility.
I hope that helps.
A screen shot might help troubleshoot the problem further is its not a privacy issue.