This has to be one of the most common errors you will encounter when tying your WF's with Infopath Forms.

So we all know that you can have instantiation/association/modification forms to use infopath forms for their end user interaction. Hey you could use ASPX forms also, but then you could row to china in a little boat as well - not necessarily the smartest thing to do.

Now, one of the most common errors you will run into is, you will follow each and every step, and then when the whole darned thing gets compiled and deployed, during the form rendering you will get an error that tells you -

This form is not workflow enabled.

WTF? But I did browser enable it. :-)

Well - here is the skinny.

Most books will tell ya to go to Tools --> Form Options, and change the security setting from "Automatically Determine" to "Domain". See, what's going on is, Automatically determine will give it "too low security rights", so a simpler approach is, "Domain", which means, as long as you are within a doman - you're good! But what if you have no domain? Well - then you get the above error :-).

So either

a) Use certificates to grant appropriate access. OR

b) Change it to Full Trust. (recommended only for development environments).

Are these horrible options? I'd wager no, because I bet you are not going to deploy Infopath forms facing the WWW due to CAL licensing implications. So 99/100 times, you are within a domain, and when you are not - use a certificate.

Not so bad eh?