error in Clib.fopen()

Hi I have a requirement to read / write data from / to a file. I have a created a file called test.txt in  C:\test.txt in my local machine. I am testing it using my local siebel client installed in my local machine.

Below is the pseudocode code that i am using:

function Service_PreInvokeMethod (MethodName, Inputs, Outputs)

{

var file = Clib.fopen("C:\test.txt", "wt+");

TheApplication().RaiseErrorText("Hi");

return (CancelOperation);

}

When i try to simulate using the Business Service Simulator i am getting the below error:

Siebel eScript runtime error occured in procedure 'fopen' of Service [Wrtie to File]: