How do I reset a field which has type AutoID to start again from count 1 after deleting all the records.Currently it starts from the next sequence.?   

AutoID field cannot be reset in a repository. This is an internally generated integer by MDM.
You will have to create a new repository using the schema of original repository for new set of Auto IDs starting from 1.

Ans2:Instead of creating new repository, just recreate the AutoID field. This will server your purpose it is not required to create the repository again

—

We have integrated SAP MDM with the Portal using the Standard iViews provided by SAP.

We have Item Details iViews, which we also use to create a new record in the table. There are some popup buttons for the lookup fields to search for values.

Currently we have set the session time out for portal as 30 mins. If the session is opened for a long time, ie after the session is timed out, we are getting a error {null} in the Portal.
Can we change this and provide a meaningful message. We are using MDM 7.1 SP03.?

Solution
The message you are seeing comes from the MDM Connector saying that the connection was already released.
Would be nice to have a “nicer” error message or to be able to change the message at design time, but would be a feature request as it is currently not supported in MDM Standard iViews.

Hope this information helps,
Idan