PUT operation response shows 500-SQL error

Hi,

I am using the following REST service.

http://www.thomas-bayer.com/sqlrest/PRODUCT/

It supports the following operations: GET, HEAD, POST, PUT, DELETE, TRACE, OPTIONS

GET and POST operations worked for me but when I try to update an existing product using PUT I get a "500-SQL error"  in response.I am not sure if it's an issue with the service or I am doing something wrong? 

I tried with the Resource field set to /sqlrest/PRODUCT/ and that throws an HTTP Status 500 - Error: java.lang.IllegalStateException: Cannot call sendError() after the response has been committed

Thanks.

GET & PUT operation on Product # 2: