Error when adding a trigger for filesize[item] on Windows

[Valerie]

Hey guys,
I am getting this error when I try to add a trigger for a filesize on a window host.
---

[ERROR:Invalid trigger expression]
No such host (HAL) or monitored parameter (filesize[c:\boot.ini])

The trigger is configured this way, and there really are an item for filesize[c:\boot.ini] for this Host:
Name: System:File: File size of c:\boot.ini was changed
Expression:{HAL:filesize[c:\boot.ini].diff(0)}>0

Any ideas what might be the problem?
And by the way, would there be a "coolest" way to check if boot.ini was changed on a windows host?

Thanks

[bbrendon]

Checksum would be a cooler way. I know the win32 defaults in zabbix have or had a checksum item, but I'm not sure if it works. I have all mine disabled.

I just tried cksum[c:\config.sys] ... didn't work.

[Valerie]

Thanks for the reply bbrendon, but yeah chksum seems to have the same behavior when adding a trigger from its item.