Red caution sign when booting into Recovery topic

Hey guys, I was planning to unlock my HTC Desire C using Desire_C_All-In-One_Kit_v2.0 but every time i try to unlock the boot-loader it gets stuck showing a red exclamation mark after showing the green circulating arrows. I tried several ways to get into recovery via USB/ADB and using the hardware buttons. Please someone help me out. Thanks in advance.
Thought this info might be helpful-
*** LOCKED ***
GOLFU PVT SHIP S_ON RL
HBOOT-1.28.0000
RADIO-1.19.98.02
eMMC-boot
May 17 2012:19:28