Can't run executable file on Ubuntu, terminal expects sudo, or gives errors like “Invalid or incomplete multibyte or wide character”

Question

I'm trying to run executable files on Ubuntu, but it's not working, although the exact same executable file works fine on others' machines, which are also running Ubuntu 12.04 like me. Based on this, I asked a question here: Executing compiled file on Ubuntu

But now I realize the issue isn't in my compiled file. Because I wrote a very simple .cpp file and tested it, but Ubuntu still didn't run it.

This is my simple test.cpp:

#include <stdio.h>
#include <stdlib.h>

int main( int argc, char **argv ) 
{
 printf ("Hello, this test worked!");
return 0;
}

Then I compiled it:

g++ `pkg-config --cflags opencv` -o test test.cpp

And then tried to run it:

./test

But I get an error:

bash: ./test: Permission denied

So I try with sudo:

sudo ./test

which asks me for my user password, which I give, but then it says:

sudo: ./test: command not found

So how can I run executable files at all?

Edit

I've got this Ubuntu installed on top of Windows, using the Wubi installer.

When I run:

pkg-config --cflags opencv

I get this:

-I/usr/local/include/opencv -I/usr/local/include  

When I run

df .

It says:

Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/loop0      17596475 6112377  11484098  35% /

And when I run:

cat /proc/mounts

Then this is the output:

rootfs / rootfs rw 0 0
sysfs /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0
proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0
udev /dev devtmpfs rw,relatime,size=1944900k,nr_inodes=486225,mode=755 0 0
devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0
tmpfs /run tmpfs rw,nosuid,relatime,size=781788k,mode=755 0 0
/dev/sda4 /host fuseblk rw,nosuid,nodev,relatime,user_id=0,group_id=0,allow_other,blksize=4096 0 0
/dev/loop0 / ext3 rw,relatime,errors=continue,user_xattr,acl,barrier=1,data=ordered 0 0
none /sys/fs/fuse/connections fusectl rw,relatime 0 0
none /sys/kernel/debug debugfs rw,relatime 0 0
none /sys/kernel/security securityfs rw,relatime 0 0
none /run/lock tmpfs rw,nosuid,nodev,noexec,relatime,size=5120k 0 0
none /run/shm tmpfs rw,nosuid,nodev,relatime 0 0
gvfs-fuse-daemon /home/asaaki/.gvfs fuse.gvfs-fuse-daemon rw,nosuid,nodev,relatime,user_id=1000,group_id=1000 0 0

Answer 1

Aren't you compiling it wrong? Shouldn't it be like:

g++ `pkg-config --cflags opencv` -o test.cpp test

or

g++ `pkg-config --cflags opencv` test.cpp -o  test