It's because in the package control file 'Section' is set to 'utils', which won't work with the application manager. It only accepts Sections in 'user'.[*] There are three ways to fix it:

1) - The author modifies the control file and makes a new package
2) - or you install the existing one by downloading, sudo gainroot, dpkg -i gps_clockd_1.0-3_armel.deb
3) - or you try the modified package that I attach here (untested), which is the original but with a very small change: Section is now 'user/utils' instead of 'utils'.

EDIT: Footnote added:
[*] This need for the debian package section to be 'user' or 'user/*' is a specific OS200x/Application Manager issue, and not used by other Linux/Debian platforms. Presumably it's done this way as a method to "filter" packages that are allowed to be installed by the user vs. packages that can only be installed as superuser (root).