FileRead Error 1591

1591: FileRead: Line too Long

File = AskFileName( "Select Plotfile", "C:\TEMP", "All Files |*.*|", "", 1 )
FilePtr = FileOpen( File, "READ" )
if !FilePtr
Message( "ERROR", "can't read %PltDatei% " )
exit
endif
PlotTyp = -1
Record = FileRead( FilePtr )
while Record != "*EOF*" && PlotTyp < 0
Spr = StrUpper( Record )
if StrIndex( Spr, "PU;", 1, @FWDSCAN ) > 0 then PlotTyp = 1 ; HPGL
if StrIndex( Spr, "PS-ADOBE", 1, @FWDSCAN ) > 0 then PlotTyp = 2 ; PS
if StrIndex( Spr, "HPGL2", 1, @FWDSCAN ) > 0 then PlotTyp = 3 ; HPGL2
Record = FileRead( FilePtr )
endwhile ; EOF
FileClose( FilePtr )
Message( "INFO", "Plottyp %PlotTyp%" )
exit