data loss to External HD

[KEVIN Lock]

I have transferred lots of photographs to an external HD (Lacie 
250gb).  When transferring I get messages saying that some names are 
too long.  Also on trying to open photos from the Lacie HD messages 
tell me that the file is damaged and possibly truncated.   Some pics 
show truncations.   I do not get those messages or problems  on the 
internal HD.     Wassup?

TIA
Kev