During the use of the last OpenCL release I've got the following message :
C:\OpenCL\runtime\src\runtime\memory.cpp:104: guarantee(hostMem_ != 0)
I don't know the reason... but it appear once I use "mem write only" for a buffer. Sorry, but I have no more information right now :-(
Are you getting same message with latest OpenCL release? Could you please give us testcase which shows this message?