Error getting status: Cannot find license file

:confused:I have a floating license for Altera software including Quartus II, Modelsim SE, Nios II. I can't setup a license server successfully. I don't know why.

I click start lmtools,select the server,click the server status tab,and click 'perform status enquiry'. And it shows me as following:

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Status

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Flexible License Manager status on Tue 5/8/2012 08:44

[Detecting lmgrd processes...]

Error getting status: Cannot find license file.

The license files (or license server system network addresses) attempted are

listed below. Use LM_LICENSE_FILE to use a different license file,

or contact your software provider for a license file.

License path: C:\altera\LICENSE.DAT;

FLEXnet Licensing error:-1,71

I could not find from related materials and the licensing center. So I am trying to post here with a hope that someone who has similar experience or knows related material can help to give me a solution or a clue.Thank you.