I have not been able to recreate this error. Can you post the .pkt file? (You will need to change the .pkt to .zip in order to attach.)
Kati Mercier, P.E.
Co-author of "Mastering AutoCAD Civil 3D 2013" AutoCAD Civil 3D 2013 Certified Professional and AutoCAD 2013 Certified Professional AU2012 Speaker::: CI3001: Reverse Engineering with Subassembly Composer for AutoCAD Civil 3D AU2011 Speaker::: CI4252: Create Subassemblies That Think Outside the Box With Subassembly Composer for AutoCAD® Civil 3D®