The file ybtlphsv.dll is a component of Yahoo! Messenger with BT Communicator from Yahoo! Inc. Yahoo! Messenger is an instant messaging client that includes extra communication protocols to work through it. This version of Messenger allowed BT (British Telecommunications) to use their own software through the Messenger service.
BT Communicator was discontinued in 2006, so this copy of Messenger may be obsolete. If you get an error with the ybtlphsv dynamic link library file this program will not work properly. You can try to fix it by checking your registry for errors.
You should regularly scan your registry and fix any errors you find. This is called cleaning your registry, and is a huge task due to the thousands of entries in the registry. But keeping the registry clean will prevent errors and speed up your system.
Use ZookaWare PC Cleaner to find and fix every registry error on your computer. ZookaWare PC Cleaner has a 60-day money-back guarantee, so give it a try when you need to clean up the computer.