./snort -d ./log ppp1

ok, i think i see somthing here..

you cd to
/home/prodiakl/snort-0.9.0
then you execute snort like this
./snort -d ./log ppp1

now this would mean that this log directory that you are specifying on the command line would be at /home/prodiakl/snort-0.9.0/log which you later say you created in /var/log/snort so this should be run like this
/home/prodiakl/snort-0.9.0/snort -d /var/log/snort ppp1
now that will remove the problem i stated above.
and if you havn't already you'll most definately want to double check your snort.conf.

now onto the pcap error. Do you have libpcap installed? I'm not sure how you can tell, but you should check (i'm sure someone here can tell you how).. and you'll want to recompile your kernel, it's a learning experience. also have you tried logging in as root and running that command as opposed to logging in as prodiakl and su'ing to root. perhaps it's a permission problem not allowing a process started by prodiakl to use the pcap library. (just a wild guess).

But i'm sure you could get some more help if you posted what distribution, and versions of your kernel and pcap libraries.

after reading this i'm not sure i actually gave any help or just rambled... hope i helped though.