First, I don't work for NCH. Sounds like you have a real problem. I have been using IVM for a few years now and I think it works great. I have had a few issues over the years but found they were mostly my fault. Have you contacted tech support? If you purchase tech support I am sure they will take care of you as they have me. I purchased tech support for the first few months to make sure they would help in case of initial set up problems. They did. This is nothing more than a discussion forum for people to talk about user issues that others have had to help work out those issues and it has been very helpful to me. I think if I had your problem I would count more on tech support than this forum.
That being said: If I remember correctly, I tried to move the folder that IVM was loaded in at one point and it caused all kinds of problems. Even using different folders for the OGM's caused problems if I remember. Somewhere on your computer there has to be the file that you are hearing. Search for all audio files (mp3, wav) and listen to all that you don't recognize. My guess is you will find it. The IVM mey be pointed to a file that is in the wrong place and is playing the first file it finds. If you want to backup your IVM and send it to me I can look at it for you. May help, may not. I have not upgraded yet but plan to after the first of the year because if the SIP support and a few other things (if they are still in business).