Cisco ASA 5505's and "No more processes"

Today i received an error when trying to upgrade the ASDM image on an ASA 5505.  I was copying the new binary via FTP, and this is what i got:

#copy ftp://xxxxx:xxxxx@x.x.x.x/cisco/asm-649-103.bin flash:
Accessing ftp://xxxxx:xxxxx@x.x.x.x/cisco/asm-649-103.bin
%Error reading ftp://xxxxx:xxxxx@x.x.x.x/cisco/asm-649-103.bin (No more processes)

Of course there were no hits on google for this particular error, and "No more processes" sounded very strange.  In the end, the issue was that i misspelled the filename, leaving out the d in asdm.  Obviously this was my fault, but it seems fairly shortsighted for Cisco to use such an obscure error message when something along the lines of "File not found" would have made more sense.