I had to fix another error first.
Error in main (line 14)
It looks like you added the letter "o" instead of the number 0 for the last 2 values.
The red text that follows the warning is there to help you find and fix the error.
The number of columns in A must be the same as the number of variables.
The error pointing back to main is the one you should look at:
Error in main (line 23)
You say you have 7 variables, but Aineq contains 8 values. Change your nvars input to 8 (or Aineq and Aeq to 7 values) and this warning and error will go away..