Xterm: Cannot connect to display

[Haritha_Jayaram]

When I try to execute the code xterm h1 h2, an error pops up stating that it cannot connect to the display. Could anyone please help me sought this error. Thanks in advance. 

[Steven Schweda]

> When I try to execute the code [...]

   On what are you trying "to execute the code"?

      uname -a

> [...] xterm h1 h2,

   "h1"?  "h2"?

   What are you using as an X server (on what)?

> [...] an error pops up [...]

   Actual message?

> [...] cannot connect to the display. [...]

   What is the display?

      echo $DISPLAY