error: Unable to copy file. The process cannot ..

Question

Hi! I have an application, which contains 2 components: a server component (C#) and a client component (asp.net). both components use the same database, developped in sql server. if one component is running and if i'm trying to run the other, i get this error: 

Unable to copy file. The process cannot access the file because it is being used by another process. What should i do?thanks!