Jin, one thing I have learned is there are LOTS of folks here that can help. May be post an image in one of the galleries (you can remove it later if you feel the need). Also, FP4+ is a very good 'old tech.' film, like Kodak Plus-X. Stick to the combo you are having a problem with and resolve it, you will be glad you did and will LEARN a great deal in the process. Read, re-read all the steps you will go through, make certain that the process area is light tight for film loading, and that the tank is light tight - lid is snug, not removed at wrong time etc. If the tank is plastic make sure there are no cracks in it.d
Last, developer is cheap - maybe not in price, but in terms of problems, just use it one-shot. I think most here do that and it removes the issue of the developer.
Again, check temp of the chemicals, check dilution of developer, check the tank for light leaks, and run some more film through.
Keep us posted, we have all been through these kinds of problems.