An error occured in communication with the BW server.--urgent

Hi all,

Can anybody help me.

i got 1 issue like ,when iam trying to executing query, iam getting the error pop up screen like

'An error occured in communication with BW server'

'Due to this ,the Connection Has To be Closed'.

Detailed Description:

1)No space left in SHARED MEMORY.

2)An exception with the type CX_SY_EXPORT_NO_SHARED_MEMORY occured,but with neither...

3)Program error in class SAPMSSY1 method:UNCAUGHT_EXCEPTION.

Could any body help me,it very urgent....