  We show that all vector bundles over CP^2 which are not spin admit a complete
metric with nonnegative sectional curvature. In the proof we construct a
nonnegatively curved metric on the corresponding principle bundle by showing
that it admits a cohomogeneity one action with singular orbits of codimension
2. This is closely related to the problem of when an action of G on the base of
an L principle bundle lifts to the total space, such that the lift commutes
with L. We solve this lifting problem for all SO(k) principle bundles over a
4-dimensional simply connected base B with G a cohomogeneity one action on B.
