Why can you not wholesale a contract for a deed?

[Paige Rommel]

Hi All, 

My husband and I were setting up a deal in Texas. The deal was a vacant lot that a cash buyer was going to turn around and build a house on. We were going to do a double close. As we progressed through the deal, we found out that the person we were acquiring the lot from had a contract for deed. Our attorney informed us that we cannot purchase on a contract for deed property. Can anyone explain why? Is there a way to still make money off of this property?