Depending on your settings in Access 2003, Access 2007 might appear to eat your custom toolbars. Don't worry, they're easy enough to find, if you know where to look.
Recently, Arthur Fuller, a friend and colleague, had a mystery on his hands after updating an Access 2003 database to Access 2007. The 2003 version contained a custom toolbar that simply disappeared in Access 2007. He eventually found the custom toolbar hiding on the Add-Ins tab.
This 2007 behavior is as designed. When you open a legacy database that contains custom toolbars, there are two possibilities: If you replaced 2003's default menu bar with a custom bar object, 2007 will display the custom toolbar; when you open an .mdb file that maintains 2003's standard menu bar, 2007 displays custom toolbars on the Add-Ins tab. In this case, each group on 2007's Add-Ins tab corresponds to a custom toolbar from your .mdb file.
Custom toolbars must be visible in the 2003 database to appear on the Access 2007 Add-Ins tab. If an .mdb file doesn't contain a custom toolbar, Access 2007 hides the Add-Ins tab.