Yeah, that's more like it.  38 bytes is what I expect for compressed private keys:

0x80 + 32-byte private key + 0x01 + 4-byte checksum

The 0x01 indicates it's a compressed key, and the address is computed differently.  In a way that Armory doesn't understand yet.  Another thing that will be supported in the new wallet format when it's done.

I actually have a chunk of code in the import dialog that detects you put in a compressed private key, but apparently that is malfunctioning.  I just tried it, and it gave the too-big error instead of telling you that it's a format Armory doesn't support yet.  I'll spend a couple minutes looking for that.