I ran into the same issue last week and basically used similar things Erik Peterson did. The file had been exported from an engineer using C3D as an Autocad v2010 file. After importing and zooming extents it went out approximately 16 light years. First I tried modifying the file in Bricscad and re-importing but it made no difference. Next with only the CAD layers selected I ran Project Cleanup. It left some objects at coordinate 0,0 but at least brought the project into a visible range. Like Erik I highlighted the area outside the project and deleted. After that zoom extents was just doing the actual project area. For the record I've been using v4.12 since it's release and until this incident I have not had issues with importing CAD files. In my opinion the file I was sent was not a "clean" file but still had some C3D items that showed as rectangular boxes with AECC labeling.
I just ran through the procedure using the Exide.dwg file. It behaved just like the file I had issues with. When I opened it in Bricscad a window opened with information about Proxies. The file seems to have been created with Civil 3D. Here's the info from Bricscad.
The drawing has proxy objects.
Application name: AcDbPersSubentManager
Number of proxies: 1, of which 0 entities
Application name: AcMapDisplayManagement
Number of proxies: 9, of which 0 entities
Application name: AeccBuildingSite100
Product Desc: AutoCAD Civil 3D
Company: Autodesk,Inc.
WEB Address: www.autodesk.com
Number of proxies: 3, of which 0 entities
Application name: AeccHydrology100
Product Desc: AutoCAD Civil 3D
Company: Autodesk,Inc.
WEB Address: www.autodesk.com
Number of proxies: 4, of which 0 entities
Application name: AeccLand100
Product Desc: AutoCAD Civil 3D
Company: Autodesk,Inc.
WEB Address: www.autodesk.com
Number of proxies: 13, of which 0 entities
Application name: AeccNetwork100
Product Desc: AutoCAD Civil 3D
Company: Autodesk,Inc.
WEB Address: www.autodesk.com
Number of proxies: 3, of which 0 entities
Application name: AeccParamPart100
Product Desc: AutoCAD Civil 3D
Company: Autodesk,Inc.
WEB Address: www.autodesk.com
Number of proxies: 33, of which 0 entities
Application name: AeccPressurePipes100
Product Desc: AutoCAD Civil 3D
Company: Autodesk,Inc.
WEB Address: www.autodesk.com
Number of proxies: 1, of which 0 entities
Application name: ObjectDBX Classes
Number of proxies: 11, of which 0 entities