which kind of package can we install on N800? application_i386.deb or application_armel.deb?

When I run dpkg-buildpackage -rfakeroot under armel target, I got the error message:
mmap: Permission denied
dpkg-architecture: failure: dpkg --print-architecture failed:
dpkg-buildpackage: failure: dpkg-architecture gave error exit status 255

Who can tell me how to make a armel package.?

Thanks!

I could be wrong but I think you need scratchbox on some other Linux box to create armel packages compatible with the tablet. If the application is a debian armel package you might be better off using Qole's easy debian package and install whatever debian package you want in Qole's debian image.

Or use py2deb package python app

You can install "application_armel.deb"
On which linux version (host) are you running scratchbox?

I hope to know how to make armel package with scratchbox.

"On which linux version (host) are you running scratchbox?"

On what did you install scratchbox?

My linux version is 2.6.24-19-generic Ubuntu

You should read the INSTALL file.