tc filter problem

[Bruno Wolff III]

I am trying to use the htb traffic shaping example from the advanced
routing howto and the tc filter commands aren't working. tc's error
messages seem to be nearly content free and I haven't been able to
figure out or guess what the problem is. It appears to be something
after the 'u32' in the following sample:
[root at bruno bruno]# tc filter add dev ppp0 parent 1:0 protocol ip prio 10 u32 match ip tos 0x10 0xff  flowid 1:10
RTNETLINK answers: Invalid argument

All four  of the tc filter commands in the script produce this same
error message.