Urgent: Problem in adding data file in tablespace

I am facing a prob while adding data file in tablespace. the error is :-

can't open log file '/oracle/DEV/sapreorg/0610131852.ext'.

Press enter to continue.

SAPDBA:Error opening logfile for writing logheader.

SAPDBA:Please check(i.e. free space in directory SAPREORG). Segmentation fault.

kindly reply ASAP. my e-mail id is ashutoshrai2001@yahoo.com