I'll supply a few links about forms at the end, but this is a good example why we at the office felt forms were dead on arrival. They can require that Outlook be the same version and that VBA, VB runtimes be installed and enabled. Some privacy software such as McAffee or others can thwart forms as well.
To recap, the creator of the form may have all that is needed enabled on their machine but then needs to enable the same on each machine they want the form to function. After a few weeks of this we decided to dump forms and go back to other methods.
Light reading:
http://support.microsoft.com/?kbid=146636
http://www.slipstick.com/addins/mssampleapps.htm
http://support.microsoft.com/?kbid=290655
Someone in my office has created a message form by adding 6 fields to the basic form. He published it and tested it and everything seemed OK. However when he completes the fields and sends it out the recipient only sees a default message screen with the text in the message area.
If the recipient tries to reply to the form they see the normal Office message reply screen. However if the recipient tries to forward the message the original form appears and the fields can be filled in. Why doesn't the recipient see the original form when he first receives it and how can we correct this problem.
Any help would be greatly appreciated.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic