I wrote a program that uses POSIX memory-mapping function (`mmap`)

The program takes a file (`a.dat`) and memory-maps it for reading/writing.

Due to errors in the program, every time I run the program a file with some weird names (e.g., `?d?P?^z??d?P?^z?`) is
created. The error is resolved but I am not able to delete the files.

I am not able to delete it either using command line or by select/deleting from window manager.

So how should I delete it? I'm using Ubuntu 11.04.