Updating project from Unity iPhone 1.7 to Unity3: Internal Compiler error

Hi, I'm getting the following error after upgrade to Unity3:

Unhandled Exception: System.ArgumentException: Trying to emit a local from a different ILGenerator. at System.Reflection.Emit.ILGenerator.Emit (OpCode opcode, System.Reflection.Emit.LocalBuilder local) [0x00000] in :0 at Mono.CSharp.LocalInfo.EmitAssign (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.VariableReference.EmitAssign (Mono.CSharp.EmitContext ec, Mono.CSharp.Expression source, Boolean leave_copy, Boolean prepare_for_load) [0x00000] in :0 at Mono.CSharp.Catch.DoEmit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.Statement.Emit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.TryCatch.DoEmit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.Statement.Emit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.Block.DoEmit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.Block.Emit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.ExplicitBlock.Emit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.If.DoEmit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.Statement.Emit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.Block.DoEmit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.Block.Emit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.Block.DoEmit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.Block.Emit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.Block.DoEmit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.Block.Emit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.Iterator.EmitMoveNext (Mono.CSharp.EmitContext ec, Mono.CSharp.Block original_block) [0x00000] in :0 at Mono.CSharp.IteratorStatement.DoEmit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.Statement.Emit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.Block.DoEmit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.Block.Emit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.ExplicitBlock.Emit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.ToplevelBlock.Emit (Mono.CSharp.EmitContext ec) [0x00000] in :0 at Mono.CSharp.MethodData.Emit (Mono.CSharp.DeclSpace parent) [0x00000] in :0 at Mono.CSharp.MethodOrOperator.Emit () [0x00000] in :0 at Mono.CSharp.Method.Emit () [0x00000] in :0

Any guess on what it could be? Thanks!