Perhaps the install was corrupt. Try it again with this version. 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.
Speech to text isn't very useful, as it doesn't parse the text to the associated video. You'd be better off with a service that specializes in captioning. Here's one
Output can be an SSA or other suitable format to import into Videopad or a caption-capable viewer, such as MPC-BE, that is loaded with your exported file.