Text Import Error: Index exceeds matrix dimensions

I am importing a number of text files and converting them to Matlab format using the code below (Note: the entire code is not included, just up to the portion where I am having issues). Most of them are running through just fine, but several (6 out of 20) are getting hung up. Below the code is the error message I am getting. I have scanned my files for inconsistencies between those that work and those that don't but cannot find any.

Can anyone see what I am missing/misunderstanding?

Thank you in advance for your help.

P.W.

% Scan file for locations of key parameters

loopdone=0;
count=1;
channamecount=0;
while loopdone==0
    currentcell=textscan(fileID,'%s',1,'delimiter', {'\n'});currentline=currentcell{1,1};        

%Load line of data

% search for Number of Channels
        if strncmp(currentline,'DM_NumLogChans=',15)==1
            numchan=str2num(currentline{1}(16:(length(currentline{1}))));        
        end

% search for Number of Data modes
        if strncmp(currentline,'DM_NumDataModes=',16)==1
            numdatamodes=str2num(currentline{1}(17:(length(currentline{1}))));   
        end

% search for channel names
        if strncmp(currentline,'DM_ChanName=',12)==1
            channamecount=channamecount+1;
            channameraw(channamecount,1)=currentline;   %extract channel name
        end

% search for Data start
        if strcmp(currentline,'DM_Start=')==1
            dataline=count+1;
            loopdone=1;                                 
        end

% search for Sample rate
        if strncmp(currentline,'DM_SampleRate=',14)==1
            samplerate=str2num(currentline{1}(15:(length(currentline{1}))));   
        end

          count=count+1;
      end

% cleanup channel names data
    begintext=strfind(channameraw, '@');
    endtext=strfind(channameraw, '.RN_');

      for count=1:length(channameraw)
          channame{count}=channameraw{count}(1,begintext{count}+1:endtext{count}-1);
      end

% Import Data
    rawimport = importdata(filename,'\t',dataline-1);
    numdatapoints=length(rawimport.data);

%Get serial Dates
      tempmat=char(rawimport.textdata(dataline:dataline+numdatapoints-1));
      for count=1:numdatapoints                       
          tempmat(count,11)=' ';                            
      end

Index exceeds matrix dimensions.

Error in edaq2mat (line 82)
                tempmat=char(rawimport.textdata(dataline:dataline+numdatapoints-1));

[Jan]

Please format your code properly.