Hi,
A kernel is a kernel, try uninstalling the more recent one ? Then check the level with a mixer...
Apart from the problem which you are encountering : you might want to take note that the ZRAM module might not be configured at all in your newer kernel, due to the pclos "special policy". At least this is what I could see last time I tried a 3.x.y kernel in a PCLOS box (several months ago, and I would suppose they didn't change the kernel config file since). And one of the interesting things in the Openbox versions is having the zram module enabled and at work : it makes the whole system even more responsive.
You can check this with the following command in a terminal as simple user:
zgrep ZRAM /proc/config.gz
here it returns:
CONFIG_ZRAM=m
# CONFIG_ZRAM_DEBUG is not set
m : for "module", so it can be loaded, and unloaded at will. the second line "is not set" does not matter for us users, of course.
If you check, let me know the result ?