@freetools in your case it seems to me that the problem is related with with your theme or maybe another plugin and not with postTabs. Using Firebug (or the equivalent tool in your browser of choice) you will see in the console the following error in the JS:
ReferenceError: Cufon is not defined in script.js?ver=1 (line 62)
It is likely that if you downgrade to the postTabs version you were using before the problem will remain confirming that it is not related with the plugin.
@vytaulla51 the error in your site is similar but it is not the same as in @freetols’s site. jQuery is included by default in WordPress but for some reason it is included in your site (or at least not in the link you sent). It is likely that your theme or a plugin is removing it from the script queue and that is what is preventing the plugin from working properly.
Please check version 2.10.3 and let me know if it fixes the problem in your case. It might not fix it depending on how and when jQuery is being removed from the script queue.