Error in vb.net Service Application

Question

Hi,

I have created a service application in vb.net. This service get records from MS-Access database and send mail to particular user.

I have tested this service in 5 machine. In 3 Machine it is working fine. but in two machine it is throwing Exception which is below.

Exception : "The provider could not determine the Object value. For example, the row was just created, the default for the Object column was not available, and the consumer had not yet set a new Object value."

I am confused. can any one guide me where i am wrong.

Thanks in advance.

Regards
Dharmchand Dhingra