octave error on vista

[bharat]

i am running octave 3.0.0 on windows vista machine.

recently when i type "help <topic-name" i get following
error

example : help plot

AllocationBase 0x0, BaseAddress 0x715B0000, RegionSize 0x150000
D:\install\octave\msys\bin\sed.exe: **** couldnt reserve space
for cygwins heap, win32 error 0.

i have tried uninstalling and reinstalling all different versions
but the problem continues.

any suggestions??

rgds
bharat