Well i didnt really know where to post this =(, if you think its wrongly placed just move it =P
I don't know if other Pascal versions show each code error, but FPC doesn't.
If you got one this encouragement killer errors use Ctrl+F with your error code number.

001: Invalid function number.
002: File not found.
003: Path not found.
004: Too many open files.
005: File access denied.
006: Invalid file handle.
012: Invalid file access code.
015: Invalid drive number.
016: Cannot remove current directory.
017: Cannot rename across drives.
018: No More Files.
100: Disk read error.
101: Disk write error.
102: File not assigned. <----got this one hundreds of times.
103: File not open.
104: File not open for input.
105: File not open for output.
106: Invalid numeric format.
150: Disk is write-protected.
151: Unknown unit.
152: Drive not ready.
153: Unknown command.
154: CRC error in data.
155: Bad drive request structure length.
156: Disk seek error.
157: Unknown media type.
158: Sector not found.
159: Printer out of paper.
160: Device write fault.
161: Device read fault.
162: Hardware failure.
200: Division by zero.
201: Range check error.
202: Stack overflow error.
203: Heap overflow error.
204: Invalid pointer operation.
205: Floating point overflow.
206: Floating point underflow.
207: Invalid floating point operation.
208: Overlay manager not installed.
209: Overlay file read error.
210: Object not initialized.
211: Call to abstract method.
212: Stream registration error.
213: Collection index out of range.
214: Collection overflow error.
215: Arithmetic overflow error.
216: General Protection fault.

Hi there is a "Pascal and Delphi" section under "Software Development". You can post your question there.