Whenever you get an error always say what line it is on. Assuming the error is when you execute the SQL, things to check are
make sure "employeenamecmbbx.Text" returns what you expect.
Next go through all the fields in your select (allowances, basicsalary etc) and ensure they all exist in the employeeregistration table and that there are no spelling mistakes.
Also you have an extra comma here
change that to
"BankName,AccountName,BankBranch,AccountNo " &