MX Pavement and Subgrade Design Error: Bad Record number

Hi.

I have a 29 km corridor. I have done the pavement and sub grade design for initial 4 km and extracted quantity and cross section. Due to discontinuity in the terrain data, I am trying to do the pavement design for  last 22 km stretch, where ground data is available. But, while performing the Pavement and Subgrade design, I am repeatedly getting error saying "Bad Record Number". I am following the below steps:

1.Design Tab-Pavement and Subgrade Design Command

2. Specifying model, mask, start end etc.

3. Pavement Layer Design.

I am getting the error after step 3, and sometime after step 2. Kindly tell me what mistake I am doing and what steps I shall follow.

I'm using MX Roads SS4.

Thanks in advance.