watchpoint question

hi,
I want to break whenever the value of a memory location changes.
For example there is a variable var @ location 0x102030.
i want to break whenever the value at 0x102030 changes,
how can i do this, the fact is that 'var' can be accessed
at several random locations in my code. I tired using the watchpoint,
But I am getting the following error,

"Can't clear hardware watchpoints without the 'Z2' (write-watchpoint)
packet."

By the way I am doing remote debugging.

Am i missing something here.
thanks
sinbad