Unexpected error in tar command

I am running Fedora 17 x86_64. I use very much tar command, and today i used it like this:

I was in /home/acaribe/acaribeW/D_ACAD

tar czvf D_ACAD.tar.gz *

This is supposed to create the tar file with that name, which contains everything in D_ACAD.

The following error followed:

"
tar (child): D_ACAD.tar.gz: Cannot open: Permission denied
ACR/
tar (child): error is not recoverable:
Exiting nowACR/grade.bak
"

I don' t know the reason for this error. In other directories under /home/ , the command succeeds, as expected.

I have no idea where from, came that ACR/. A "locate ACR" brings many occurrences of 'ACR' , names of directories, and parts of names of files. Thats occurs bucause ACR are my inicials.

I would very much to understand what is going on inside linux: that is the first time in thousands of uses of that command.

Thanks in advace

Alberto Caribé da Rocha