Report scheduled: the file saved at File system of zero size

Hi

We have scheduled reports in Business Objects 4.0 on Unix platform

It was working fine until yesterday the report ran successfully but the file saved on unix system was of zero size

If i open the file from scheduled history the file was generated with data. But save with zero size on the file system

The directory has space also to save the 5Mb file

There were 5 such reports all saved with zero file size.

Please help