From my experience, the "Cannot Auto-Warp so far" message appears when you try to warp into a planet's (in this case Eve) sphere of influence from the sphere of influence of another body (except Kerbol, sometimes. Kerbol is weird). For example, say I did a flyby of the Mun and was on an escape trajectory of Kerbin. While I am in the Mun's sphere of influence (or SOI) I cannot time warp directly to that of Kerbol. In order to resolve this, you have to warp into the middle SOI first. So for you, if you're within Kerbin's SOI, warp to Kerbol's and then from there to Eve's. Also, if you have extra deltaV, it's good to get down your periapsis a bit so that if it moves during warp, it will stay within the planet's SOI.