Websphere Studio (Application Developer) 5.1.2

Starting yesterday giving me problems. When I went in to login today, I get the
following error message at startup:  
"Problems during startup. Check the ".log" file
in the ".metadata" directory of your workspace"

This is the latest error in that .log file:
"
!SESSION ----------------------------------------------------------------------
!ENTRY org.eclipse.core.launcher 4 0 Jul 25, 2007 14:10:50.256
!MESSAGE Exception launching the Eclipse Platform:
!STACK
java.lang.reflect.InvocationTargetException: java.lang.RuntimeException: Fatal
Error: Unable to locate matching org.eclipse.core.runtime plug-in.
	at java.lang.Throwable.<init>(Throwable.java:52)
	at java.lang.Throwable.<init>(Throwable.java:66)
	at
org.eclipse.core.internal.boot.PlatformConfiguration.locateDefaultPlugins(Platfo
rmConfiguration.java:2264)
	at
org.eclipse.core.internal.boot.PlatformConfiguration.<init>(PlatformConfig
uration.java:903)
	at
org.eclipse.core.internal.boot.PlatformConfiguration.startup(PlatformConfigurati
on.java:1368)
	at
org.eclipse.core.internal.boot.InternalBootLoader.initialize(InternalBootLoader.
java:582)
	at
org.eclipse.core.internal.boot.InternalBootLoader.startup(InternalBootLoader.jav
a:1035)
	at
org.eclipse.core.internal.boot.InternalBootLoader.run(InternalBootLoader.java:83
8)
	at org.eclipse.core.boot.BootLoader.run(BootLoader.java:461)
	at java.lang.reflect.AccessibleObject.invokeL(AccessibleObject.java:207)
	at java.lang.reflect.Method.invoke(Method.java:271)
	at org.eclipse.core.launcher.Main.basicRun(Main.java:291)
	at org.eclipse.core.launcher.Main.run(Main.java:747)
	at org.eclipse.core.launcher.Main.main(Main.java:583)
"

I am now unable to use my WSAD for work. Can anybody help?

thanks!
Matt