Hi,
It looks like you didn't enable the network analyst extension. Please make sure to go through step 6:
[INDENT]6.Enable the Network Analyst extension.
[INDENT]a.Click Customize > Extensions.
[INDENT][/INDENT]The Extensions dialog box opens.[/INDENT]
[INDENT]b.Check Network Analyst.
c.Click Close. [/INDENT][/INDENT]
Thanks.
Anna