DataSets, DataView and Exceptions

While we have pretty good results with the datasets and dataadapters,
we recently hit an issue wich dataviews.
The situation is as follows: We have a rather complex dataset
made up of more than 20 tables. Usually we have absolutely no
problems with data binding and update operations. However,
if we use dataview (of course with some filters) for databinding
and add a row to either the table underlying the dataview or to the
dataview itselft, exceptions can be thrown. These exceptions can not
be predicted and debugging showed a null reference exception in the
row state! We saw this problem with .NET 1.1, but SP1 has really made
things worse.

Any suggestion what is wrong here would be greatly
appreciated.