From the error message, it looks like the definition for the DRMManager class can't be found. This could be because the library defining the AIR APIs isn't in the project path (but I believe this should be automatic as long as you created a desktop project). More likely, you are building a SWF version 9, rather than SWF version 10. You can set this in the project properties on the compiler page. Look at the target Flash Player field and make sure it is 10.x rather than 9.x. More recent versions of Flex Builder handle this better, so I recommend upgrading, if you can.
In some old versions of Flex Builder, I have had to edit the .actionscriptProperties file to set add htmlPlayerVersion="10.0.0" attribute to the compiler tag. If the above doesn't work, you might try that.
It is working with latest builder. But I got an anther problem; that is the link (source code) which I have given is working for a single file to get the voucher. But I want to get the vouchers for the multiple files at a time. How can I do this. could you pls help me.
Thanks & Regards
I think you just have to make a request for each voucher separately.