having problem on backup exec

Follow the steps

1. Click on tools select options
2. In the right pane select Catalogs
3. Uncheck Use Media Based Catalogs
4. Click OK and then try to catalog that media again

Update the status

If the above steps doesnt help to resolve refer this KB here the solution given

When trying to restore media, "The selected media was not found in the catalogs" occurs

http://www.symantec.com/business/support/index?page=content&id=TECH16628

and when I tried to restore data from the rest of tapes

Doing a long erase on a tape will not make the other tapes data unavailable.

Do you have a backup set spanned over erased tape and the other tape you are trying to restore?

Both Quick and long erases does not change the media label.

I think you mean the other tapes  already in the catalog lists

those tapes are working fine.i can restore them.Problem is on only few tapes that i did use for last week backup

Whether those details are present in the catalogs or not depends upon your catalog level(Fully cataloged/Truncated/ Uncataloged).  

Long erased tape also belongs to your last week backup?

yes long erased tape is one of the last week backup tapes.

i don't really know do i just wait to finsish catalog tapes.

or just install MDAC?

Above KB provided MDAC also an one of the cause!

yup the above link for MDAC is broken anyway i did install MDAC2.8 from another source

it still doesn't help me .still prompt to do catalog

Remove the filter which you have set

Begning backup date and Ending backup date and see if it make any difference .

Also When you ran the catalog did you got any byte count ??

Do you have any data on the tape from which you are trying to restore ?