As of today, even patch 31 is available.
I'd think you have probably a 64-bit Unicode system. If so, go to support.sap.com -> Software downloads -> Support packages and patches -> K -> SAP Kernel 64-bit Unicode -> SAP Kernel 7.42 64-bit Unicode, then select your operating system from the menu, go to #Database independent and look for the dw_31 SAR file.
EDIT: The above is for Kernel version 7.42. What kernel are you on?
Message was edited by: Tamas Hoznek