Blender 2.44 for Linux has no problems with importing Maple .wrl graphics. I exported this graphics with Blender to .ply and .obj format. The commercial software Deep Exploration has no problems with opening these files, but You are right, Meshlab 1.1.1 can not open these files. So i think the problem is in Meshlab.
Another way to produce .u3d files from Maple graphics with free software(there are no problems with Deep Exploration, You can directly open a Maple VRML file and export it to U3D): Display Maple graphics with use of Javaview, export it to a .obj file, read it with Meshlab and convert to .u3d ,see the example at:http://www.math.muni.cz/~plch/jezura2.pdf.