Hi,

First Always try to use dynamic form if u dont bother it being slightly bloated/slower than simple (ADD MOD DEL)ADD MODIFY/update DEL.

secondly if u try to do some changes in already created form u get some weird out of earth errors.. which only martians may encounter.
sometimes so bizzare javascript errors within dreamweaver itself.

so to solve this i sometimes play a trick..
as mentioned above i utilize the user persistence of ADDT..

1 . Recreate everything.. This is last solution.
2. try blindly adding the field u want.. if u get weird errors use
the undo button (so dont close the changed file in dreamweaver while ur testing ).
3. to convert something to hidden field just edit the code by hand.
4. if blindly adding the field results into errors undo
close dreamweaver and reopen it.
retry the operation it should work.
5.> if the above step fails then...
delete all fields below the field u want to add from the ADDT manage dynamic form. and then re add whatever u want..
this will 99% work.
6.> now.. u can sometimes also try the try of directly going to server behaviors panel and double click the insert/update transaction .. etc..
and add fields to them..
and manually type in the fields name into the form physically.

try these tricks ...

NOTE : for Goodness sake always keep a backup of whole project folder. and especially the file u r changing..
if u have versioning system.. then its a boon over everything.