I was using my other N900 and I get also a
"...not compatible" with the other N900 and the above deb.

The protocol says:
"/usr/bin/dpkg-deb -f '/home/user/MyDocs/Sound/gstreamer-tools_0.10.25-0maemo4+0m5_armel.deb'
Package must have "Section: user/FOO" to be considered compatible.
FAILED: gstreamer0.10-tools ( ) | gstreamer0.8-tools"

"gstreamer0.8-tools" makes me wonder.
I have some /usr/lib/libgstreamer-0.10.so.0.22.0 installed.
and some /usr/share/gst-python/0.10/...

Any ideas?