ESI problem with salary less then the limit

Hi Experts ,

I am really tensed with things happening as regards ESI calculation is concerned an its understating in SAP .

there is an EE whose ESI was calculated till March 2014 and in April 2014 even though his salary is less that 15000 , his ESI is not calculated

and i am cheking this log , where the ESI nominal basis is showing 19000  can sombdy plz xplain how it is 19000 whn salry it self is less than 15000

please this is happning in PRD , some body come to my rescue plzzz

Thank you

Arun