infopath limitation

It is very important to understand the limitation of infopath 2007. From high level, web based infopath is very powerful but it comes with several limitations.

1. No native write to SQL databases. The ease of use of establing an ADO connection to SQL or Access, and being able to query and write back to a database is lost. Instead you will probably need to talk to the DB via a web service.
   
2. No roundtripping for cascading picklists. Something I do all the time is have one picklist be a filter for another picklist. Common example, pick a state, which then filters the city field dropdown. Can't do that in a web form.
3. Summary list of controls that aren't supported in web forms:
   ComboBox,Multiple-Selection List Box
   Master/Detail,Bulleted, Numbered and Plain List
   Picture ,Ink Picture ,Vertical Label
   Scrolling and Horizontal Region ,Horizontal Repeating Table
   Choice Group ,Repeating Choice Group
   Choice Section ,Repeating Recursive Section
   ActiveX Controls

Refer to this article for more details, MSDN article.

With this limitation, this shows you how to perform debugging.