You didn't run out of space, you just don't know how your blogging software works.

Enable paging links so you can see additional articles in a category. See this page in the user manual and look for the part about checking the Show paging links on default category view checkbox.

cheers for that. funnily enough i did find that, but only after i'd studiously moved loads of entries across into other folders. now i have to steel myself for moving them back or changing the way the folders work... i'm still having a think about it as it's annoyingly time-consuming.
i do still hate the software, though, you'd think that it would warn you when your stuff was dropping off the bottom.

also, any ideas as to how i can change the noxious colour scheme (the options are very limited) and have more than 5 recent comments showing? cheers.

I don't know how much access you have to the underlying code, but I think you can edit your templates through your Blog Admin. The bit that applies to Recent Comments is this:

{{if blog.recent_comments}}
<div class="component">
<div class="componentHead">Recent Comments</div>
<div class="componentContent">
<div class="componentRecentComments">
{{loop name=blog.recent_comments limit=5}}
<div class="componentRecentCommentsItem">
<a href="{{permalink_url}}">{{if title}}{{title}}{{else}}Untitled{{/if}}</a>
</div>
{{/loop}}
</div> <!-- componetRecentComments -->
</div> <!-- componentContent -->
</div> <!-- component -->
{{/if}} <!-- blog.recent_comments -->

Everything I've read says "up to 5 recent comments can be displayed" but you MIGHT be able to up that by changing the number in the template.
Colour is much easier: go to the Control Panel, select Look and Feel, select "colors" and choose a template (I suspect you already know this!) but here is an article on fully customising your colour scheme.