Time I'm Splitting Does Not Match Finished Product

I'm having a hard time trying to explain this. Please forgive me; I'm new to media editing and I do it at home for fun. But it's almost stopped being fun because...........:(

The internet radio station I DJ for will replay recorded broadcasts of my two live shows if I send it to them. I've been having a horrible time since I upgraded the Media Splitter two weeks ago (the $4.95 upgrade) with some of this. I always stop my audio in the splitter exactly where I want it to cut, but after I save it and replay my finished product in Windows Media Player my audio stops up to ten seconds before where I actually cut it in the media splitter. So then I tried letting it extend an extra ten seconds of audio before I cut it, but then sometimes it cut off EVEN SOONER than the first time around or it would leave the extra ten seconds in. I ended up sending in a finished product last night that had a section in it where I said "Um" followed with a section with the tail end of a song because I could not get it to cut where I actually wanted it to cut and I needed to join those two pieces and get it to the station ASAP and my eyballs were ready to fall out of my head from the eye strain of doing it over and over and over again until I gave up. This keeps happening regardless of whether or not I slide the yellow arrow across the bar and then set a marker where I want to stop it or if I put in the exact times I want it to start or stop. :mad:

Any help would be greatly appreciated. :(