unable to open worksheet

Hi All,

        I am getting an error message "error while running worksheet window java.lang.reflect.invocationtargetexception", Please advice. Demantra Version details ,

7.3.1 48 0 13-FEB-13

javaconsol:

Java Plug-in 1.6.0_18
Using JRE version 1.6.0_18-b07 Java HotSpot(TM) Client VM
User home directory = C:\Users\vineeth-v
----------------------------------------------------
c:   clear console window
f:   finalize objects on finalization queue
g:   garbage collect
h:   display this help message
l:   dump classloader list
m:   print memory usage
o:   trigger logging
q:   hide console
r:   reload policy configuration
s:   dump system and deployment properties
t:   dump thread list
v:   dump thread stack
x:   clear classloader cache
0-5: set trace level to <n>