[peterska2]

replacing

{firstaltcolor}

with

alt1

and

{secondaltcolor}

with

alt2

should do the job. I haven't tested it though.

Also

$session[sessionhash]&forumid=

should be replaced with

$session[sessionurl]&f=

and

$session[sessionhash]&threadid=

should be

$session[sessionurl]&t=