It is very hard to give general solutions to this problem, but try to keep all values in your problem in the order of magnitude of 1 by proper scaling. Almost parallel constraints are also not very good for numerical stability. You can consult the author as well if you encounter numerical problems, but please remember that it is very easy to formulate an infeasible LP problem, so be sure there is a solution. The work of Jeroen Dirks made the transition from the basic version 1.5 to the full version 2.0 possible. He contributed the procedural interface, a built-in MPS reader, and many fixes and enhancements to the code.
Bug reports are welcome, as well as success stories.