What version of VP is being used? Install the latest. For licensed users upgrades are free for up to six months from purchase date. After that, VP will continue to fully function but a fee will be required in order to register the newest. Retain your old install file and registration info.
If that doesn't help, please share the project and indicate which clip is to be sped up and by how much. Sharing is easy, takes little time and is the best way to get help.
Just follow the PORTABLE PROJECT instructions here... http://nch.invisionzone.com/topic/23659-tips-for-getting-help-on-this-forum/
If it contains sensitive material link it in a personal message (PM). Click the envelope above. It won't be passed on or retained. Use FILE|SAVE PORTABLE PROJECT AS, not simply SAVE PROJECT, and don't forget to share it.