[X4U] keychain login problems

[nk]

I am setting up mail on one of my macs, and I am asked for my  
keychain password.

I typed the only password I have for that mac, and I am told "wrong  
password"

I try several times, no dice.  uppercase lower case (I know how I  
typed it) but am still told "No"

am I understanding correctly what it wants? It's the computer  
password for when I want to administer that mac? (I am admin)

or is it asking for some other password?

thank you!

nk