You should normally reboot after reinstalling Java. Otherwise it can leave the system a touch unstable. http://www.gnutellaforums.com/333278-post2.html applies to LW but same principle applies. Just get the FW offline installer instead. Online installers anything related to LW 'suck' to say the least. They poison preferences folders with obsolete partial versions that corrupt later attempted installations. Delete your FW prefs folder also if you have one; How to delete your FrostWire Preferences folder (click on link)

LW has been on a money cost cutting exercise for several years & unfortunately that same code passes across to FrostWire. Who no doubt play the same game with saving costs on hosting of the installer files. ie: each user without knowing downloads a partial installer file inside their preferences folder they without knowing upload to people using the online installers. This does NOT show in the download OR upload windows. They upload in secret to help speed up online installations & save costs of running servers to host the entire installers. That's why offline (entire) installers are so much larger, they contain 'all' the files contents needed for the installation. Thus users are paying for a portion of the bandwidth needed for 'others' to install their program, rather than LW or FW paying for it all. Offline installers are oh so much more reliable!!!