Yes, we saw issues with Dwarf4 attribues in gcc4.5 files under OpenSUSE 11. Currently, the Intel IDB Debugger stops at such unsupported dwarf attributes with an assertion failure. We will have a fix with the upcoming Intel Composer XE 2011 Update that ignores such non-essential attributes.
Do you have a small reproducer that shows the probem? If not, could you please provide the .debug_line dump (as file attachment) from the executable, e.g.
$ readelf -wl -x ".debug_line"