tests hang on Windows 7
OS: Windows 7

```
$: git describe
v0.7.0rc1-1778-g9d4f557
```

```
$: python
Enthought Python Distribution -- www.enthought.com
Version: 7.1-1 (32-bit)

>>> import tables
>>> tables.__version__
'2.4.0'
>>>
```

```
$: nosetests -v pandas
...
test_verbose_import (pandas.io.tests.test_parsers.TestParsers) ... ok
test_xlsx_table (pandas.io.tests.test_parsers.TestParsers) ... ok
test_append (pandas.io.tests.test_pytables.TestHDFStore) ...
```

The tests then hang and the python process quits. 
