Reproduced with Inkscape 0.48+devel r10130 on OS X 10.5.8 (i386)
Alternative steps to reproduce:
1) draw horizontal line
2) add Bend LPE and node-edit the bend path (symmetrically)
3) switch to select tool
4) add gears effect
-> LPEs are stacked and the first gear is rendered ok
5) reselect Bend LPE and node-edit bend-path
-> Inkscape hangs
Reproduced with Inkscape 0.48+devel r10130 on OS X 10.5.8 (i386)
Alternative steps to reproduce:
1) draw horizontal line
2) add Bend LPE and node-edit the bend path (symmetrically)
3) switch to select tool
4) add gears effect
-> LPEs are stacked and the first gear is rendered ok
5) reselect Bend LPE and node-edit bend-path
-> Inkscape hangs