It is hard to gess the Error. I Enable "show Script Errors", but there are only some message lines I wrote in previous.

1. When I click on "Add row" link, the added-form  displays and occurs the Error 

Line: 43

char: 3

Error: Expected ';'

Code: 0

Url: ...

2. When I click "update" to add the new row, another error is displayed

Line: 54

char: 1

Error: 'dnn_ctr401_EditUserDefinedTable_Rich text_edit_Rich text ...' is null or not an object

code: 0

Url: http://localhost/<...>/tabid/59/ctl/edit/mid/401/UserDefinedRowId/3/Default.aspx

please, You may try to add column type "Rich Text(Html)" to see if It could have occured the error. May be, I use the old version of User Defined Table?

Thanks, 

I think I know you issue: http://support.dotnetnuke.com/Default.aspx?p=15&i=4101 

Try a simple column name without any white spaces or other special characters or upgrade to UDT3.3.6