you can not manaully chage the expire date or duplicate the image for the images that are contorled by SLP, 

if you would like to do that you need to follow below

nbstlutil cancel -backupid <backupid>

then try changing the expire date and also duplicating..., but it will not carry any SLP retenctions or images... you have to take care it manually.

http://www.symantec.com/business/support/index?page=content&id=TECH170086

If you try to expire the image or the image copies manually that are not SLP-complete, the request fails with a 1573 error. To expire the image or images, you can do one of the following:

• Wait for the image or copy to become SLP-complete.
• Use the nbstlutil cancel command to terminate the SLP processing.
• Add the -force_not_complete option to the bpexpdate command to force the expiration even if the image or copy is not SLP-complete.

Date you specified is beyond 2038. Try to set date before 2038.

My point also - infinity backup are 2038 in Netbackup 

Retention Periods with end dates beyond 2038, excluding Infinity on Windows

http://www.symantec.com/docs/HOWTO68516

Try doing :

bpexpdate -recalculate [-backupid backup_id] -d infinity

yes you're right, it was a mistake of keyboard typing, i typed 2014.

but now firned i have a serious problem, the image has an expire date in the past, so i can't no longer change the expire time and date, please need your help, i have to change the expire date.

when i typed  the command bpexpdate -recalculate i got the message : Failed to process an image whose expiration date is in the past.

please, i need your help before the backup clean up job pass and delete this image.

thanks in advance

You can "import" expired backups if tapes have never been overwritten. Follow the steps described in this guide page 789.

http://www.symantec.com/docs/DOC5159

hello,

i did the importation but, the image has been deleted :(

i tried to increase the clean up time to prevent the cleanup to delete the images, but the job start many time, even i increased the time intervall...

What is the date on your NBU master server?

12/12/2014 is NOT in the past. Or did you maybe make some more typo errors? 
Like 10/12/2014 perhaps?

There is no return from expiration of backup on disk. The expiration triggers nbdelete on media server that will also delete the data on disk. So, not possible to import.

Use extreme care with bpexpdate in future.
The command is followed by a confirmation message.
Read this message carefully before pressing 'y'.

hello marianne,

i just typed :

bpexpdate -recalculate -backupid backupid_11111111111

and i got the message, when i connfirmed it, i verified with bpimagelist, and i had the bad info, i saw that the date has been changed and the image has been expire (the date was with two days in the past).

the date on the master server was correct...

a bpexpdate -recalculate does not modify any dates according to my testing.