Why is it not possible to move the blk* files to another server?

Hello,

I set up some server and Server1 has the whole blk* files.
I stopped the Server1 and moved all blk* files to Server 2.

But if I start the bitcoind daemon, I get an error:

Code:

XCEPTION: St13runtime_error
CDB() : can't open database file blkindex.dat, error 22
bitcoin in AppInit()

terminate called after throwing an instance of 'std::runtime_error'
what(): CDB() : can't open database file blkindex.dat, error 22

I have tried a lot of things, but it does not work.
The only thing is to use -loadblock=file but it takes a while.

So why it is not possible to move the files to another server
and start the daemon?