OK, it maybe a problem with the SQL/Query string........ are you 100% sure that

"SELECT UserName,Password FROM data"

UserName and Password are names of columns
data is the name of the table

i noticed there is no space after the first comma try "SELECT [UserName], [Password] FROM [data]"

is there a prefix that your missing?, im not good with database setups but you sometimes need a prefix ... ."SELECT [UserName], [Password] FROM [DatabaseName].[dbo].[data]"

check the file yourself and double check these