Were you using extra AIs, or anything?
I use all default graphics (except for BattleMoons/MassiveBaseShip), and the datafiles load before your problem occured, so:
If it
is an actual file missing, it's likely to be an AI file...
I will do everything I can to solve your problem, but I do have two exams and a couple projects this week, so I can't do much until the weekend

.
I'd suggest downloading the latest (v2.4) anyways.
There was a short period of time (a few hours) when I had a bad Version of P&Nv2.3c posted; If you donloaded it a few weeks ago, you may have gotten that.
------------------
The latest info on
Pirates & Nomads (forum thread).
-<
Download the Latest Version of P&N>- (just extract to your SE4 folder)
--<
Download my HomeComing scenario>- (For P&N v2.3b)
--<
P&N V2 AI patch>- (V2
only, for the AIs included in ZIPs from v2.0 to v2.3, prevents rare RCEs)
-<
Download P&N Classic>- (The final release of P&N v1.x, just extract to your SE4 folder)
-<
Download compatible EMPs for P&N v1.2 through v1.7>-
-<
Download SJs latest AI Patcher>-
-<
Download my FTL propulsion map>- (ships can travel FTL StarTrek/B5/StarWars style)
-<
Download my LAN helper>- (Auto-searches for new turns on a filesharing-enabled LAN)
Visit
My Homepage
Other Links:
-<
Play By Web>-
-<
Schlock Mercenary>- (great space-based webcartoon) -<
First Strip>-
-<
8-bit Theater>- (fun comic with the pixellated FF1 characters)
<SE4Code>
MpN R*-A RM(L) RP+ TCP- Fq++ FR!++ P? A+/- Sf+ Nd- L $ M++++ Pw!+
</SE4Code>