"Runtime Error" is saying the program has encountered an instruction that is impossible to execute. If you are using a program that's putting up that message, you need to contact the people you got the software from. You might be able to work around it by entering a different value but that's a serious error that should not appear in de-bugged software.
If you are writing a program, look at the properties for the object producing the error and provide ways for the program to gracefully deal with an incorrect value rather than shutting down. There have been reports of this error in programs written in VB6 when using a masked edit box.
Answered Jul 27, 2011
Edited Jul 27, 2011