qt creator 2.5.0 can not save symbol link as symbol

Developer has a Link-based Synergy workarea, in Linux env. Then he startup qt creator-2.5.0 in Linux, and open files from the workarea and start to edit code, using QT creator. During save, QT creator always prompt error, telling "Error while saving files: Cannot write file /...../..../a.c. Disk full?". But if developers use QT creator to edit "true file, not symbol link" and no error occurs during save.

(And we can sure, there is enough disk space left for saving files)

Any clues to this error? What should developer do to avoid this error?