There is a max limit of 2Gb on the table size.
However this limit is different per table depending on the block size set in the BDE when the table was built.
Paradox tables hold a max of 65536 blocks, which can be block sizes of 1,2,4,16,32kb therefore the max sizes per table can be (in approx sizes):
1kb blocks - 64Mb
2Kb blocks - 128Mb
4Kb blocks - 256mb
16Kb blocks - 1Gb
32Kb blocks - 2Gb
Also bear in mind that the index files also have the same limitation so if you have large indexes (i.e. Largish alpha fields) this also can cause index corruption as the table grows in size.
From the figures in the first post my very, very rough guess is that you are using tables of 2Kb block size.
You can get more detail about the block size of a table by using the Table Utility tool in Paradox, you don't have to repair the table just use the utility to open a table and you will get details on the block size being used.
Hopefully this helps,
Rgds
Jonathan
Regds
Jonathan