Greetings, Though this does not solve your problem think of it as a different approach to it. I would suggest setting the input record separator to a different value to get your file to be read in differently. Assuming your example file is representative of your input...

#!/usr/bin/perl -w
use strict;

#of course this assumes the example file is in the exact 
#format expected. The following line is basically the 
#line containing a lone 'c' at the beginning and a whole
#bunch of spaces (your comment cards).
#remember that $/ can't handle regexp... though it sure
#would be cooler if it did.
local $/ = "c                                                         
+                      ";

while (<DATA>){
    print "\n=====chunk start=======\n";
    print $_;
    print "\n=====chunk stop=======\n";
}

#from the example data you gave.
__DATA__
m8    92234.30c 0.0071  92235.30c 0.9300  92238.30c 0.06289           
+          
      8016.30c 2.0      42000.30c  2.5                                
+          
c                                                                     
+          
c   BeO(2.86) Axial Reflector TD=3.01 / 95%=2.86                      
+          
m9    4009.30c 0.5  8016.30c 0.5                                      
+          
mt9   beo.01t                                                         
+          
c                                                                     
+          
c   BeO(?AllgenCalc) Radial Reflectpr TD=3.01 / 95%=2.86              
+          
m10    4009.30c 0.5  8016.30c 0.5                                     
+          
mt10   beo.01t                                                        
+          
c                                                                     
+          
c   He/Xe(.0218) (72/28) ~.55 mol/L at 300K,1.38MPa, 39.6 g/mol       
+          
m11     2004.30c 0.7                                                  
+          
       54124.30c 0.00027  54126.30c 0.00027  54128.30c 0.00576        
+          
       54129.30c 0.07932  54130.30c 0.01224  54131.30c 0.06354        
+          
       54132.30c 0.08067  54134.30c 0.03132  54136.30c 0.02661        
+          
c                                                                     
+          
c   Sodium(0.929) RoomTemp = .97 g/cc,  at melt = .929 g/cc           
+          
c    Liquid = .929 - .000244*(t-371) (t in K) Handbook Ch&Ph          
+          
m12   11023.30c   1.0                      $ Na (.929 g/cc) frozen/voi
+d         
c                                                                     
+          
c   Lithium(.515) RoomTemp = .534 g/cc,  at melt = .515 g/cc          
+          
c    Liquid = .515 - .000101*(t-454) (t in K) Handbook Ch&Ph
[download]

So essentially you can get the file read in in chunks and deal with each chunk with your regexp. Oh and here is the output from above.

=====chunk start=======
m8    92234.30c 0.0071  92235.30c 0.9300  92238.30c 0.06289           
+          
      8016.30c 2.0      42000.30c  2.5                                
+          
c                                                                     
+          
=====chunk stop=======

=====chunk start=======

c   BeO(2.86) Axial Reflector TD=3.01 / 95%=2.86                      
+          
m9    4009.30c 0.5  8016.30c 0.5                                      
+          
mt9   beo.01t                                                         
+          
c                                                                     
+          
=====chunk stop=======

=====chunk start=======

c   BeO(?AllgenCalc) Radial Reflectpr TD=3.01 / 95%=2.86              
+          
m10    4009.30c 0.5  8016.30c 0.5                                     
+          
mt10   beo.01t                                                        
+          
c                                                                     
+          
=====chunk stop=======

=====chunk start=======

c   He/Xe(.0218) (72/28) ~.55 mol/L at 300K,1.38MPa, 39.6 g/mol       
+          
m11     2004.30c 0.7                                                  
+          
       54124.30c 0.00027  54126.30c 0.00027  54128.30c 0.00576        
+          
       54129.30c 0.07932  54130.30c 0.01224  54131.30c 0.06354        
+          
       54132.30c 0.08067  54134.30c 0.03132  54136.30c 0.02661        
+          
c                                                                     
+          
=====chunk stop=======

=====chunk start=======

c   Sodium(0.929) RoomTemp = .97 g/cc,  at melt = .929 g/cc           
+          
c    Liquid = .929 - .000244*(t-371) (t in K) Handbook Ch&Ph          
+          
m12   11023.30c   1.0                      $ Na (.929 g/cc) frozen/voi
+d         
c                                                                     
+          
=====chunk stop=======

=====chunk start=======

c   Lithium(.515) RoomTemp = .534 g/cc,  at melt = .515 g/cc          
+          
c    Liquid = .515 - .000101*(t-454) (t in K) Handbook Ch&Ph          
+          


=====chunk stop=======
[download]

Does that make sense?

-InjunJoel