I don't want my users to be able to go back to a previous page in the form. Is there a way to remove the BACK button?

Yes, you can do that.

-- First, in your form properties, change the settings below as noted:

Include Submit Button: NO

Paging Include: NO

(If your last page is a thank you page, you can still check that box here, but leave Paging Include set to NO.)

Then SAVE PROPERTIES to save the element.

-- Now go to page 1 of your form. Create a new element, as noted below:

Type: Submit button

Label: Next Page

Name: nextPage1 (or whatever you want to call it)

Value: Next Page

-- Then go to the element's ADVANCED tab, and in the ACTIONSCRIPT section, do the following:

Type: Library

Actions: Click (checkmark)

Script: FF::ff_validate_nextpage

Then SAVE PROPERTIES to save the element.

Do that for each page EXCEPT the one on which the submit button will be placed, as well as 

your Thank You page, if you have specified one.

-- On the page that will contain your submit button, create a new element with settings as follows:

Type: Submit button

Label: Submit

Name: submit (or whatever you want to call it)

Value: Submit

-- Then go to the element's ADVANCED tab, and in the ACTIONSCRIPT section, do the following:

Type: Library

Actions: Click (checkmark)

Script: FF::ff_validate_submit

Then SAVE PROPERTIES to save the element.

-- Once all of your buttons have been created, click on the SAVE icon in the upper right-hand corner of the screen to save the form itself.

You will likely have to make some CSS adjustments to your SUBMIT button settings to get the placement of it the way you want it, but this will at least get the function there for you. :-)