A 504 Error on a Philips DPM is from firmware level v02.35 onwards: multiple file entries found.  The device indicates the error and corrects the FAT automatically.  This should only occur on Windows 2000 platforms.  This is not an error but an indication for automatic correction.
Recommended Fix:
The real error producing corrupt files on the MMC is caused by a property of Windows 2000: Connecting a DPM device to USB takes several seconds of dialogue with the PC. Also, data transfer in Windows 2000 can take up to 30 seconds of additional data exchange after download or upload. Windows incorrectly indicates to the user that data transfer has been finished, and thesmiley face” on the device,s display may also be misleading. Watch the yellow blinking LED in the device that correctly identifies that data transfer is in process. Do not unplug the DPM from USB Docking Station while the yellow LED is blinking before data transfer has been completed.  If disconnected before the end of data transfer, files residing on the MMC can become corrupted. Corrupted files on the MMC can also influence new dictations created on this MMC. To avoid this, firmware V02.35 (V0 1.04) handles the corrupt files.”Error 504″ shown in a triangle on the device,s display: Multiple file entries found. The device indicates the error and corrects the FAT automatically. This should occur together with Windows 2000 platforms only. This is not an error but an indication for automatic correction.
Verification Source: In-house testing