Diamonds boss Garry Hill has already admitted that he wants to bring in a more experienced forward to partner Simeon Jackson, Michael Rankine or Lee Tomlin up front.
Blue Square Premier rivals Aldershot were also interested in signing Sills but pulled out of the running, meaning Diamonds are favourites to sign him despite competition from Stevenage.
Shots assistant boss Martin Kuhl said: "Unless the wage demands are sorted out, any deal for Tim is dead I'm afraid.
"I have been told that he is going somewhere else now and, while we were interested in bringing him back, we can't afford his wages.
"We would like to speak to him but we are so far away from each other in terms of wages that it is not something that's going to happen at the moment.
Boro chairman Phil Wallace added: "We've been unsuccessful in our attempt to sign a striker from a League Two club but we'll continue to look around."
All indications now point towards Hill snapping up the 6ft 2in former Oxford frontman to make his sixth new signing for the club.
Source: http://www.confguide.com/newsArticle.do?id=6663