Newbie needs help

[eluser]ecotypes[/eluser]
Hi -

I'm very new (I'm on my first site, third page!) and suspecting that I may have some routing or .htaccess problem.

I have not attempted to remove index.php from the URLs.

URLs without parameters work and I get where I want to go.

http://www.shirleydenton.com/index.php/plants/pindex

works

I printed out what is in the segments, it is correct. Segment 1 is plants. Secment 2 is pindex, Segment 3 is undefined, Segment 4 is undefined

I then try to use the URL to pass data in the segments

http://www.shirleydenton.com/index.php/p...ex/alpha/A

I get a 404 error.

Is this some type of routing problem? If so, I'm not understanding the myriad of posts on routing and .htaccess

I have no .htaccess file at this point -- do I need one to get this to function?
My site is on BlueHost

Thank you in advance.