I am planning on installing bamboo on a wood subfloor. Previously the area had ceramic tile and oak laminate which we removed. There are places were the first ply of subfloor came up when removing the tile, creating gashes. There is a small amount of tile underlayment and adhesive still left on the subfloor at this time. I was planning on using a belt sander to get rid of the left over adhesive and smooth out the floor as much as possible, and then fill the remaining gashes with wood fill. Is this the correct method, or is there a better way of going about it?

Are you planning a naildown or gluedown installation? I will assume naidown over a wood subfloor. Sounds like your on the right track as far as smoothing out the subfloor. You may find it tough using a belt sander, but then again you may be o.k. using a rough grit paper. I usually use a Warner razor scraper to remove and smooth out/flatten. Pictures of your subfloor would help if possible. I stay away from fillers over a wood subfloor, fearing it's a matter of time and filler will start breaking loose. With a naildown...good chance you will bust filler loose with fasteners, during installation. If your just talking minor gashes,( again a picture would help), I would scrape the floor, sand the seams , roll out my underlayment, and proceed. Depending on the extent or condition of the subfloor...you may be better off sheeting out over the top of it with 1/2" plywood.