Fix inappropriate messages.

Fix two inappropriate messages.

1)
code:
throw new ArgumentNullException("Unquoted identifier parameter cannot be null")

message:
System.ArgumentNullException: Value cannot be null.
Parameter name: Unquoted identifier parameter cannot be null

2)
code:
throw new ArgumentOutOfRangeException("Unknown state: " + "Connector.State")

messaage:
System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values.
Parameter name: Unknown state: Connector.State