Well it would be nice if you could use code tags when posting your code. Also since here programmers with various backgrounds are posting and reading, a bit more elaboration on pdb file format would be nice, maybe even an example.
Q: When you say pdb are you referring to protein data bank format, or a program database file?
In any case splitting the file depends on entry format. For example if you want to split a fasta formated file that contains several entries, then you will not be splitting it by rows but by entries. Also if the number of entries is odd then you have to decide how will you deal with that.