not enough hardware breakpoints

Hello,

when I try to debug a program with insight and nios2-gdb-server, I get the following error message:

MDI error There are not enough hardware breakpointsto satisfy request. (MDXFS2ERR_TOOMANYHWBRKPTS)# -115 (nios-gdb-server.c line 768)

What's the problem? What can I do to avoid that error?