There is no "popup login" on this website. Which leads me to believe you have some sort of trojan/keylogger on your local system.
To further assist you, these questions need answered.
1. What address do you use when you access the site... .ORG or .COM

2. Are you using a MAC or PC?
3. what site is it that you are coming from when this happens?
Clear your history... Try deleting all cookies associated with ozarksjeepthing.com, there should be 7 total, no need to delete ALL cookies, just delete the OJT ones.
If you are unsure how to do that, go to the help menu of the browser you are experiencing the difficulties in and search for "remove cookies".
After the history and cookie steps, close your browser completely, including any download or bookmark windows associated with it.
Open the browser and try to recreate the event.
post up what happens.