I had the same problem and did not find any answer on the internet for solving it. Then i tried it myself and fixed it.Try these easy steps hopefully it will work >
Go to the folder where you installed TC(usually it is Program files>TC). There you will see all the necessary directories of TC like BIN,INCLUDE,CLASSLIB,LIB, etc .
Then go to the folder named INCLUDE.From there Copy the "stdio.h" and "conio.h" files and Paste them in CLASSLIB > INCLUDE