Unable to install CyanogenMod on Galaxy S2 i777

I'm trying to use ROM Manager to install the [cm-10.1.3](http://download.cyanogenmod.org/?device=i777&type=stable) ROM on my phone, but I'm getting the following error (from recovery.log): -- Installing: /sdcard/bluetooth/cm-10.1.3-i777.zip Finding update package... I:Update location: /sdcard/bluetooth/cm-10.1.3-i777.zip Opening update package... Installing update... Warning: No file_contexts script aborted: assert failed: getprop("ro.product.device") == "i777" || getprop("ro.build.product") == "i777" || getprop("ro.product.device") == "SGH-I777" || getprop("ro.build.product") == "SGH-I777" || getprop("ro.product.device") == "SGH-S959G" || getprop("ro.build.product") == "SGH-S959G" assert failed: getprop("ro.product.device") == "i777" || getprop("ro.build.product") == "i777" || getprop("ro.product.device") == "SGH-I777" || getprop("ro.build.product") == "SGH-I777" || getprop("ro.product.device") == "SGH-S959G" || getprop("ro.build.product") == "SGH-S959G" E:Error in /sdcard/bluetooth/cm-10.1.3-i777.zip (Status 7) Installation aborted. result was NULL, message is: assert failed: install_zip("/sdcard/bluetooth/cm-10.1.3-i777.zip") Here's info about my phone: Model number: SAMSUNG-SGH-I777 Android version: 4.1.2 Baseband version: I777UCMD8 Kernel version: 3.0.31-1154545-user se.infra@SEP-126 #3 SMP PREEMPT Tue Apr 23 22:10:17 KST 2013 Build number: JZO54K.I777UCMD8 Recovery: ClockworkMod 6.0.1.0 In addition, I found this set of instructions http://wiki.cyanogenmod.org/w/Install_CM_for_i777 , but using ROM Manager seems to be a much easier way to install the ROM. These instructions say to use the wipe data/factory reset option in CWM recovery - does this mean I should use the "Wipe Data and Cache" pre-installation option in ROM Manager?