Not releasing Texture Memory

I have a routine that loads many textures in to a level. I then use glDeleteTextures to supposedly clear the texture objects before using glGentextures to reaalocate for further levels. This works fine until about the 6th or so level whereupon I’m unable to load anymore textures. It appears as though the texture memory is not releasing and is accumulating to overflow (leaking). What is going on and how does one overcome this. Here is a link to another forum showing similar concerns and more info to this problem.