Console output

I used this program part for my GUI project. It shows me all info's about the external program. But it has a counter that show's me the percent of the program status, but i get this errormassage from BlitzMax:

PipeStream ReadBuffer Overflow
Process complete

In the c-source it print out the following:

if (last == 0) {
fprintf(stderr, "\r%s %d%% %0.2fs ",
header, percent, etime);
}

This is the code i use in Blitzmax:

While Process.Status()
PollSystem
If Process.pipe.ReadAvail() Then
line = Process.pipe.ReadLine()
If line <> "" Then
AddTextAreaText(textarea , line+Chr$(13))
FormatTextAreaText(textarea,10,230,460,70,lines,1,TEXTAREA_LINES)
lines=lines+1
EndIf
EndIf
If Process.err.ReadAvail() Then
line = Process.err.ReadLine()
If Line <> "" Then
AddTextAreaText(textarea , line+Chr$(13))
FormatTextAreaText(textarea,10,230,460,70,lines,1,TEXTAREA_LINES)
Lines=lines+1
EndIf
EndIf
Wend