I'm not sure what is hitting the limit.
From corel's FAQ (FAQ

doxWin

aradox & BDE Limitations:2001.05.25) :
Subject: FAQ

doxWin

aradox & BDE Limitations:2001.05.25
Version 1.0 (2000.09.22)
edited by Mike Irwin
Repost by Mike Irwin: 2001.02.05
Version 1.1 (2001.05.25)
edited by Mike Irwin: 2001.05.25
Repost by Mike Irwin: 2001.02.05
====================
0. Introduction
====================
This FAQ states the published limitations to Paradox's
functionality, grouping current knowledge. If you have
items that should be added, please contact the author.
-------------------------------
0.1 Legal Info and Disclaimers
-------------------------------
Paradox is a trademark of Corel.
Borland Database Engine (BDE) is a trademark of Inprise.
The information provided in this FAQ is provided "as is"
and is not warranted in any way. The information provided
in this FAQ is not endorsed or authorized by Corel or
Inprise in any shape, form, or manner. The editors claim
NO responsibility for ANY illegal activity regarding this
file, or as a result of someone reading this file.
You may distribute this file, as long as the copies are
complete, unaltered, and are in electronic form only.
-------------
0.2 Feedback
-------------
Please send feedback in a Corel Paradox newsgroup or the
news:comp.databases.Paradox newsgroup to any of the FAQ
Team mentioned in the "FAQ: FAQ FAQ" document.
Please preface the subject of your post with the string
"PDXWIN FAQ" to alert Team members to the function of
the message.
Please specify the FAQ name and section number the
comment applies to, if any.
==============================
1. General
==============================
These are current as of version 9 from Corel. You can
also investigate this subject at
========
2. General BDE Limitations
========
48 Clients in system
32 Sessions per client
(3.5 and earlier, 16 Bit, 32 Bit)
256 Sessions per client
(4.0 & later, 32 Bit)
64 Sessions with a cursor open per client
(4.0 & later, 32 Bit)
32 Open databases per session
(3.5 and earlier, 16 Bit, 32 Bit)
2048 Open databases per session
(4.0 & later, 32 Bit)
32 Loaded drivers
64 Sessions in system
(3.5 and earlier, 16 Bit, 32 Bit)
12288 Sessions in system
(4.0 & later, 32 Bit)
4000 Cursors per session
16 Entries in error stack
8 Table types per driver
16 Field types per driver
8 Index types per driver
48K Size of configuration (IDAPI.CFG) file
64K Max size of SQL statement (RequestLive=False)
4K Max size of SQL statement (RequestLive=True)
6K Max size of SQL statement (RequestLive=True)
(BDE 4.01&later)
16K Record buffer size (SQL and ODBC)
31 Table and field name size in characters
64 Stored procedure name size in characters
16 Fields in key
3 File extension size in characters
260 Table name length in characters
(some servers might have other limits)
260 Path and file name length in characters
260 Index name length (including pseudo-indexes)
204 Setting for MEMSIZE in BDE Administrator
127 Tables with cached updates applied
(BDE 4.0 & earlier, 32 Bit)
254 Tables with cached updates applied
(BDE 4.01 & later, 32 Bit)
380 Maximum number of fields in Table for
DbiCreateTable with Interbase
254 Maximum number of fields in Table for
DbiCreateTable with Oracle
500 Maximum number of fields in Table for
DbiCreateTable with Informix
252 Maximum number of fields in Table for
DbiCreateTable with MSSQL
250 Maximum number of fields in Table for
DbiCreateTable with ODBC, Sybase
253 Maximum number of fields in Table for
DbiCreateTable with DB2
408 Maximum number of fields used in an Interbase
Table
1000000 Maximum number of bytes per blob for ODBC
========
2. Paradox Limitations
========
127 Tables open per system
254 Tables open per system (BDE 4.01 & later)
64 Record locks on one table (16Bit) per session
255 Record locks on one table (32Bit) per session
255 Records in transactions on a table (32 Bit)
512 Open physical files
(DB, PX, MB, X??, Y??, VAL, TV)
1024 Open physical files
(DB, PX, MB, X??, Y??, VAL, TV)
(BDE 4.01 & later)
300 Users in one PDOXUSRS.NET file
255 Number of fields per table
255 Size of character fields
2 Billion records in a table
2 Billion bytes in .DB (Table) file
10800 Bytes per record for indexed tables
32750 Bytes per record for non-indexed tables
127 Number of secondary indexes per table
16 Number of fields in an index
255 Concurrent users per table
256 Megabytes of data per BLOb field
100 Passwords per session
15 Password length
63 Passwords per table
159 Fields with validity checks (32 Bit)
63 Fields with validity checks (16 Bit)
81 Maximum characters in path for tables
involved in Referential Integrity
25 Field name size in characters
Notes on Paradox Table Types
When referring to Paradox Table Types, the type number,
or"Level", is taken from theversion of Paradox with
which itwas introduced.
To move a table's level to a higher level, arrange to
include some feature that requires the use of the higher
level.