>>In SSMS try to change the settings I mentioned (SET ANSI_NULL and ANSI_NULL_DEFAULT) until you get the same error as from your application. Then you would know which setting to change from the application.
>
>I changed all the related ones and was not able to simulate the same as when it happens in the application.

Are you logging all commands as they are executed? Every time or only for error cases?

Can you post the exact failing command so may be I (or others) can figure what setting may be responsible (if indeed this is the case)?

BTW, did you change it in script right before executing the command or through the interface?

Try the first approach.