I continue to have an error message pop up constantly on my desktop screen. It refers to a startup error, and says the following:

LimeWire version 4.18.3
Java version 1.6.0_01 from Sun Microsystems Inc.
Windows XP v. 5.1 on x86
Free/total memory: 31318208/33357824

com.limegroup.gnutella.gui.GUILoader$StartupFailed Exception: .\lib\hashes (The system cannot find the file specified)
at com.limegroup.gnutella.gui.GUILoader.sanityCheck(G UILoader.java:281)
at com.limegroup.gnutella.gui.GUILoader.load(GUILoade r.java:58)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Nativ e Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknow n Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Un known Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.limegroup.gnutella.gui.Main.main(Main.java:45)

STARTUP ERROR!

This is extremely annoying. I have removed limewire and reloaded it, and get the same pop-up error message. Limewire itself does work, I have downloaded numerous songs. But this popup is annoying, not to mention my wife is annoyed about it as well.

Can anyone help me with this?

Try deleting your LW Preferences folder whilst LW is closed; instructions here: Point #2 & 3 in Fixes for Limewire (sample image included at bottom of page.) Make a note of all your settings first under tools > Options.

If still problems, check the later points such as compatibility mode in the above link.
Another possibility is your Java is semi corrupted, in which case you should re-install Java using the OFFLINE installer Download Java software from Sun Microsystems