I'm pretty sure that what you received in the email is incomplete otherwise there would be a line that begins which the word FEATURE as below. When they say encrypted they are referring to the part that comes after word "uncounted".
To install the license manually (Windows)
Go to the email, fax, or mail you received, and type or copy the license string. It looks like the following:
FEATURE MayaUnltd sgiawd 5.000 20-may-2003 uncounted 70F9BD1AC42F HOSTID=FLEXID=7-b285e673
Please check if there is an aw.dat file located within the C:FLEXLM directory.
If there is, paste or type the license into the top of the aw.dat file and save it.
If there is no file or directory there, create the C:FLEXLM directory.
Open Notepad (Start > Programs > Accessories > Notepad) and copy the license string into the new document.
Save the file from Notepad as aw.dat within the C:FLEXLM directory.