you can get rid of the %al on the %pb line, since it's completely useless as the %pb tag defines where it's positioned and the size with the values in the positions after the image name (the tag syntax is %pb|[image name]|[x-coordinate]|[y-coordinate]|[width]|height]|, substituting the labels in square brackets for the appropriate info (without the brackets, of course).
Also, you will probably need to define at least one viewport since as far as I can recall the default viewport no longer draws anything onto the screen (I may be wrong though...). Just in case, though, you can easily define a full screen viewport with %V|0|0|-|-|1|-|-|, which will use the full width and height of the screen, use the user font, and use the foreground and background colours defined in the .cfg file for the theme.
If that doesn't work, I'm not sure what else might be wrong.
Just a note: Since rockbox now uses definable viewports in the WPS, you may wish to do a lot more rework to this theme to use viewports to better align the various pieces of information rather than spaces, this way the theme will retain its layout better if someone were to decide to use a similar sized font with wider or narrower space characters.
EDIT: I also note that the RTC code in this theme is out of date. You'll need to change it to read %cH:%cM, or perhaps even add a check for 12-hr vs. 24-hr time so it can display either way: %?cf<%cH:%cM|%cI:%cM %cP> (or %cp if you want a lowercase am/pm indicator rather than an uppercase one).
As well, you're missing an image P. which means the code will halt when it tries to preload the image P for the line %?mh<%xdO|%xdP> (you could easily remove the %xdP from that line and it would fix the problem, though).