Trying to code in Java without reading some tutorials is like trying to speak in japanese without learning the language first.
Sure, you may...
Are you trying to place the boat on water and the minecart on rails?
What is the server-ip in your server.properties file set to?
What economy plugin are you using?
Here's some suggestions:
Something unique. Users like to see something unique on the server or some sort of functionality that distinguishes it...
There's this for a start. http://wiki.bukkit.org/Setting_up_a_server
Well, you're already paying your utility bills such as electricity so, a dedicated server ontop of that is an big additional expense.
Has your internal IP changed during the time from when you setup the server?
One problem with a dedicated server is that it costs like $100 per month and upwards.
Could try disabling OpenInv to see if that solves the problem since that one seems to interact with the inventory.
Can you post which plugins you have installed as it could be one interfering with the inventory?
What plugins do you have installed?
What plugins do you have installed besides that then?
What version are you using and what plugins do you have installed?
Separate names with a comma.