I have the same problem that I uploaded c program in a txt to srv1,  
type "Q" and there's no response unless restarted.
The program is workable in another srv1.
 
I have uploaded the last firmware ( - 19:09:37 - Mar 11 2008), finally this problem solved.
Below is what I have done:
 
1. After uploaded the firmware, it shows  "##zZ boot image write count: 131072". But I type "2" in TeraTerm, it wont move.
2. I use SRV1Console connect to srv1. It work normally.
3. Close SRV1Console and back to TeraTerm, I can type "2", then it moves.
4. I test with c program, it works.

Thanks. I dont notice that we shall give 'Mabc' before '2'.
I still encounter no response when executing c program.
It’s confusing that we have no idea what happened.
Up to now I just uploaded the firmware to see if the problem disappear.
Maybe Lithp wont have this issue.

Thanks. I'm used to give the c program:
 
main()
{
   int i, j, k;
   for(i = 0; i < 5; i = i + 1) {
     for(j = 0; j < 3; j = j + 1) {
      for(k = 3; k ; k = k - 1) {
        print(i);
        print(j);
        print(k);
      }
     }
   }
}
 
Now it works well with all these programs, but yesterday it indeed got no response.
I think it's strange, and someone may get confused like me.

I always use the same code to test.
Sometimes I got the text with 'zr' 'zd', what is read from user flash section:
 
         main()
{
    print("hello");
}
 - 1) {
        print(i);
        print(j);
        print(k);
      }
     }
   }
}
 
 
I guess it maybe necessary to use 'zc' to clean the flash buffer.
Or in c program, there's some unvisible char when I copy from website.
 
I just find out that every time I turn on srv1, sometimes 'Q' works and sometimes doesn't.  
And I usually use 'X', 'zd' then 'Q'. So I have some guess.

I've had no problems with the test programs, however I can't seem to get an if/then statement to work.
 
In the program below I get the error:  'semicolon expected in line 3'
 
main()  
{
  if ((sonar(1)/100)<=12)
       servo(50,50);
  else  
       print("Testing");
}  
 
All the if/then variations I've tried get the same result.
 
Am I missing something?

Interesting.  I get no response from that program at all.
 
If I put a print statement before the 'if' statement, it prints that statement fine.  However, nothing happens from the 'if' statement on.  
 
It's not frozen as I can type 'V' and get the Version info displayed...

Weird.  I cut and pasted the first one with the result I mentioned.  
 
I cut and pasted the last one and got: sonar1 =       1622
 
I re-flashed the .ldr and I get the same thing:  sonar1 =       1600         ( But nothing else after the print statement )
 
I'm using the srv1-c.ldr.2500k dated 041208.  I'm also using shamcom to transfer the files.  I can't get teraterm to complete a transfer at all.
 
 
 
 

I can't get netcat to recognize the ESC, so I can never leave the insert mode.  I tried disconnecting, then re-connecting with shamcom and was then able to ESC out of the editor.  It didn't make any difference though.
 
I'm using my local wireless network, not adhoc mode to control the srv1 at the moment.  I've not had any problems using Shamcom either, as the other program attempts seem to work fine.  It just doesn't like the 'if' statement.
 
I tried my original srv1 as well.  It doesn't have the sonar sensors, but I expect it should just give me a zero reading for the range.  This is what I got as a result:
sonar1 =          0stopnot a variable in line       10semicolon expected in line
      10    pdrive  
 
This was for the program in the last code you posted here.  Also using the srv1-c.ldr.2500k dated 041208.
 
If I use the 03 April ldr I get this response for the same program:
sonar1 =          0stopnot a variable in line       10semicolon expected in line
      10    pdrivestack_ptr = FFB00F9Cheap_ptr  = 00080000
 
I have another laptop that has linux on it and may give that a try.  I know just enough about linux to get in trouble, but I'll see what happens and let you know.