Pandas: AttributeError: 'numpy.ndarray' object has no attribute 'start'
``` python
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
from datetime import time

data = pd.read_csv('/temp/zondata/pvlog.csv', delimiter=';', parse_dates=True, index_col=1)
Gewenst = data['T_Sanyo_Open']
```

Next 2 examples(in Ipython console) gives no errors, and gives a result like the table at the bottom of this question:

``` python
Gewenst['2010']

Gewenst['2010-09']
```

Example below gives me previously described error when I want a specific bounded range of data:

``` python
Gewenst['2010-9':'2010-10']
```

I found a solution when I add this rule of code:

``` python
Gewenst = Gewenst.resample('1Min', fill_method='ffill') 
```

But I don't want to resample the data.

table:

``` python
2010-08-31 12:36:53    30.37
2010-08-31 12:45:08    28.03
2010-08-31 12:55:09    25.16
2010-08-31 13:00:09    23.28
2010-08-31 13:05:09    22.37
2010-08-31 13:10:09    21.84
2010-08-31 13:15:08    22.19
2010-08-31 13:20:09    22.41
2010-08-31 13:25:09    23.16
2010-08-31 13:35:09    23.59
2010-08-31 13:40:09    26.75
2010-08-31 13:45:09    29.47
2010-08-31 13:50:10    33.13
2010-08-31 13:55:08    35.91
2010-08-31 14:00:08    37.78
...
2013-06-07 01:35:10    40.00
2013-06-07 01:40:10    40.00
2013-06-07 01:45:10    39.50
2013-06-07 01:50:12    39.75
2013-06-07 01:55:10    39.25
2013-06-07 02:00:10    39.50
2013-06-07 02:05:11    39.25
2013-06-07 02:10:11    39.25
2013-06-07 02:15:10    38.75
2013-06-07 02:20:11    38.75
2013-06-07 02:25:11    38.75
2013-06-07 02:30:10    39.25
2013-06-07 02:40:10    39.25
2013-06-07 02:45:10    39.00
2013-06-07 02:50:10    39.25
```

Does anyone have solution, or is this a bug in Pandas?
