hi
try this
before creating table validate like this
string validate="SELECT 1 FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE='BASE TABLE' AND TABLE_NAME='" + tablename + "_GroupMaster'";
after validate like this to create
string s= "create table " + tablename + "_GroupMaster(Slno int identity(1,1),GroupId Char(7) null,GroupName varchar(150) null,Status Char(1) null,MasterId notnull)";