The wall was built to prevent East Germans from fleeing and stop an economically disastrous migration of workers.
He was trying to deal with the East Germany's refugee problem which was The East Government was extremely unpopular-so many East Germans fled to West Germany- between 1949 and 1961 2.7 million escaped to West Germany- Many of these were very skilled- such as doctors.
To make this answer short The problems that Krushchev was trying to deal with was to keep the East Germans from fleeing and to stop an economically disastrous migration of workers.
