This paper propose a cross-layer forward error control (FEC) scheme, which is designed for reliable block transfer of variable-length coded data in wireless multimedia sensor networks (WMSNs). Taking advantage of iterative techniques, and combining the PHY layer, transport layer and the application layer FEC techniques, the proposed cross-layer FEC scheme not only provides strong bit-error correction capability, but also is capable of overcoming packet losses in the multi-hop transfer. Requiring low computational complexity, this FEC scheme is suitable to be applied to the multimedia bulk data transfer in WMSNs. Simulation results show that the proposed cross-layer FEC scheme provides significant improvement on multi-hop transfer reliability of variable-length coded data.