Folks,
I've lately realized after a lot of investigation (also thanks a lot to Potemkine's help!) that it was not a "faulty" form which gave me problems (see the "Odd Form Behaviour" post) but rather Infopath 2007 itself.
All my forms, which were up to recently developed with Infopath 2003, reside on a server. The forms were working perfectly. Some of the forms have been running smoothly now for 3 years
I have recently upgraded to Infopath 2007 and thats where everything went wrong...Forms started to show bizarre behaviour. Often, when I attempt to open a form it gives the: " Infopath cannot create a new, blank form" error. This happens randomly, I can open the same form 20 times seamlessly and then it would give an error 4 times in a row after which it will work fine again - this happens with Infopath 2003 and 2007 developed forms which are opened with Infopath 2007.
We have a decent network and as I said before Infopath 2003 didn't give me the same problems.
I have a deadline for end November when a major system using SQL and Infopath 2007, which approximately 70 people will use, needs to go live. We have completed all the development on Infopath and now this. I'm pulling my hair out on this one, if someone can give me some pointers I will really, really, really appreciate it.
To summarise:
Infopath 2003 & 2007 developed forms give random errors when opened in Infopath 2007.
Operating systems are XP and Windows 7
No Sharepoint Server being used
No network problems