Please Help : Problem Posting To SQL Server

Hi there,

Can someone please explain to me what's wrong.
Here's the problem scenario.

I am using a dataset in my Delphi 3 application and it is in Edit mode.
The new values are set and then I call 'Post'
It goes to the SQL Server and using SQL Trace you can see
the ' BEGIN TRAN go' statement, followed by the update statement.
Then after a while it does a ROLLBACK TRAN and the update doesn't

Now the strange thing is I copied the update statement as it appeared in
the SQL Trace window and paste it into the SQL Query Tools Query Window.

I executed this update statement and it went throught fine.

When you try the update from the application, it hangs for 20 minutes,
come back with the following message Lock Time Out, Sql Server
Connection TimeOut.

The Delphi 2 version of the app does the same thing.

At first I thought there might be something wrong in the data, because
some  records can be updated this way from the app.
Bu now I'm not sure whether the 'Post' might be giving the problem.

Thanks in advance,