PreS: coredumb, you prove my not so subtle allusion wrong before the fact
thank you for that
nonetheless, and like i point out in my (too long) post, is it a good idea to install files from SSU manually?


don't mention it, literally ¦:-}
it looks like you won't be able to install mc 4.7.4, unless i shuffle you over the files you can't get from the SSU repositories.
but even this is actually a bad idea because the files in the SSU (Seamless Software Updates) are updates to core files of the operating system. if you start installing newer versions without access to the whole repository you will very likely get dependencies problems when trying to install never versions of software's

afraid you will have to settle with 4.6.2
in fact you may want to remove the extra-devel & testing repositories from your system, as packages there are likely to depend on newer versions of the system files provided by SSU

as a matter of fact trying to help you w/ mc gave me a very concrete & down to earth example of a discussion i was reading up at the same time.

in a nutshell, NOKIA made a few months ago a strategic change by switching from its (more or less) house build mobile device OSes (Symbian and Maemo) to microsoft's wp.
as the Maemo.org site is mostly financed by NOKIA this could of course mean trouble even though NOKIA already promised support for another year or so. thus the ppl who manage the site on a day to day basis (the Council) felt they needed to plan for the worse, namely that NOKIA will not renew its support next year.
i'll spare you the gritty details, but alas not all of Maemo is open-source and thus if Maemo.org has to survive w/out NOKIA they either have to get the closed-source parts from NOKIA or come up with some open-source alternatives.

two remarks

your problem isn't technical in nature but, as you pointed out yourself administrative. nonetheless, it gives a very concrete idea of how fragile the openness of Maemo is, if updates to the core OS are not available in the same way other packages are.

as i pointed out in the nutshell, the Council is planning for the worst.
silently, many of course hope for the best, namely that NOKIA will continue to support Maemo.
as a matter of fact NOKIA promised support for their last Maemo device (the N9) for several years and the most likely way to do that is via Maemo.org
EDIT: from reading todays post on a discussion it seems NOKIA has decided not to make use of Maemo.org to support the N9


long story cut short
i got myself a 2nd N900 a little while ago in order to have a test device for the new Maemo, namely MeeGo.
as i will keep one of the N900s as my primary phone / device under Maemo i thought about doing a couple improvements to it.
considering our failure to install mc 4.7.4 on your N900 (and some serious ethical issues on talk.Maemo.org, but that's a different very ugly story...) i think i'll head over to MeeGo right away :|

hope you can settle with mc 4.6.2
and enjoy your N900 nonetheless

PS: maybe you can to edit the title of the thread to reflect that the problem is specific to 4.7.4 without SSU?
that is, if you are able to install 4.6.2, of course.