I've spend a few of hours today going round on this one, so I thought I'd share..
As a process has been developed a certain form has been working fine but today I noticed it was failing to load with the web client just stopping at the "spinning clock" opening form. Nothing was logged in the designer's validation, the eLog table, or the event logs on the server. Using the debug mode and Visual Studio also failed to highlight anything.
This left the only option but to start deleting fields (moving fields to other forms wasn't an option as you can't publish when a field fails validation due to business objects being missing). After much saving, deleting and re-publishing I found that once I deleted a command button the form started loading again!
After more investigation it turns out it was due to the client side script that I'd attached to the button. Mistakenly I'd used the old V7 syntax - OnClick= DoSomething(); &Language=JScript rather than the new syntax.
It's a bit annoying (an understatement) as when client script failed in V7, the form loaded and you were notified of a client script error. Now there seems to be nothing and you have to grope around in the dark for a bit.
I'm hoping by posting this it's save someone else a few hours 
On a similar not how is everyone else finding the whole problem solving / debugging issue whilst developing?
On the whole I like the new direction V9 has taken however I do miss the simple eWork script during times of need. Ideally I would have left it available with an option to hook out to c# when additional power was needed. I consider myself a decent coder but some things are now taking triple the length of time to develop in V9 than they would have done in V7, however I'm hoping this will come down somewhat as familiarity sets in.
Cheers,
Paul.
