\[\left( - \frac{2}{3}a^{- 2}b^{3} \right)^{- 2} \cdot \frac{8b^{4}}{a^{2}} =\]
\[= \left( - \frac{3}{2} \right)^{2} \cdot a^{4} \cdot b^{- 6} \cdot \frac{8b^{4}}{a^{2}} =\]
\[= \frac{9a^{4}}{4b^{6}} \cdot \frac{8b^{4}}{a^{2}} = \frac{18a^{2}}{b^{2}}.\]